I. INTRODUCTION

A. Neonatal Physiologic Characteristics

1. Water metabolism

Water represents 70 to 80% of the body weight of the normal neonate
and premature baby respectively. Total body water (TBW) varies
inversely
with fat content, and prematures have less fat deposits. TBW is
distributed
into extracellular fluid (ECF) and intracellular fluid (ICF)
compartment.
The ECF compartment is one-third the TBW with sodium as principal
cation,
and chloride and bicarbonate as anions. The ICF compartment is
two-third
the TBW with potassium the principal cation. The Newborn's metabolic
rate
is high and extra energy is needed for maintenance of body temperature
and growth. A change in body water occurs upon entrance of the fetus to
his new extrauterine existence. There is a gradual decrease in body
water
and the extracellular fluid compartment with a concomitant increase in
the intracellular fluid compartment. This shift is interrupted with a
premature
birth. The newborn's body surface area is relatively much greater than
the adults and heat loss is a major factor. Insensible water loss are
from
the lung (1/3) and skin (2/3). Transepithelial (skin) water is the
major
component and decreases with increase in post-natal age. Insensible
water
loss is affected by gestational age, body temperature (radiant
warmers),
and phototherapy. Neonatal renal function is generally adequate to meet
the needs of the normal full-term infant but may be limited during
periods
of stress. Renal characteristics of newborns are a low glomerular
filtration
rate and concentration ability (limited urea in medullary interticium)
which makes them less tolerant to dehydration. The neonate is
metabolically
active and production of solute to excrete in the urine is high. The
kidney
in the newborn can only concentrate to about 400 mOsm/L initially
(500-600
mOsm/L the full-term compared to 1200 mOsm/L for an adult), and
therefore
requires 2-4 cc/kg/hr urine production to clear the renal solute load.
The older child needs about 1-2 cc/kg/hr and the adult 0.5-1 cc/kg/hr.

2. Fluid and Electrolytes Concepts

Cellular energy mediated active transport of electrolytes along
membranes
is the most important mechanism of achieving and maintaining normal
volume
and composition of fluid compartments. Infants can retain sodium but
cannot
excrete excessive sodium. Electrolytes requirements of the full-term
neonate
are: Sodium 2-3 meq/kg/day, potassium 1-2 meq/kg/day, chloride 3-5
meq/kg/day
at a rate of fluid of 100cc/kg/24 hrs for the first 10 kg of weight. As
a rule of thumb, the daily fluid requirements can be approximated too:

prematures 120-150cc/kg/24 hrs

neonates (term) 100cc/kg/24 hrs

Infants >10kg 1000cc+ 50cc/kg/24 hrs.

Special need of preterm babies fluid therapy are: conservative
approach,
consider body weight changes, sodium balance and ECF tonicity. They are
susceptible to both sodium loss and sodium and volume overloading. High
intravenous therapy can lead to patent PDA, bronchopulmonary dysplasia,
enterocolitis and intraventricular hemorrhage. Impaired ability to
excrete
a sodium load that can be amplify with surgical stress (progressive
renal
retention of sodium). Estimations of daily fluid requirements should
take
into consideration:

(1) urinary water losses,

(2) gastrointestinal losses,

(3) insensible water losses, and

(4) surgical losses (drains).

Blood Volumes estimates of help during surgical blood loss are:

premature 85-100 cc/kg,

term 85 cc/kg,

and infant 70-80 cc/kg.

The degree of dehydration can be measured by clinical parameters
such
as: body weight, tissue turgor, state of peripheral circulation,
depression
of fontanelle, dryness of the mouth and urine output. Intravenous
nutrition
is one of the major advances in neonatal surgery and will be required
when
it is obvious that the period of starvation will go beyond five days.
Oral
feeding is the best method and breast is best source. Newborn infants
requires
100-200 calories/kg/day for normal growth. This is increased during
stress,
cold, infection, surgery and trauma. Minimum daily requirement are 2-3
gm/kg of protein, 10-15 gm/kg of carbohydrate and small amount of
essential
fatty acids.

B. Variations in Individual Newborns

1. Types of Newborns Infants

a) The full-term, full-size infant with a gestational age of 38
weeks
and a body weight greater than 2500 grams (TAGA)- they received
adequate
intrauterine nutrition, passed all fetal tasks and their physiologic
functions
are predictable.

b) The preterm infant with a gestational age below 38 weeks and a
birth
weight appropriate for that age (PreTAGA);

c) The small-for-gestational-age infant (SGA) with a gestational age
over 38 weeks and a body weight below 2500 grams- has suffered growth
retardation
in utero.

d) A combination of (b) and (c), i.e., the preterm infant who is
also
small for gestational age.

The characteristic that most significantly affects the survival of
the
preterm infant is the immature state of the respiratory system. Between
27 and 28 weeks of gestation (900-1000 grams), anatomic lung
development
has progressed to the extent that extrauterine survival is possible. It
is only after 30 to 32 weeks of gestation that true alveoli are
present.
Once there is adequate lung tissue, the critical factor that decides
extrauterine
adaptation and survival of the preterm infant is his capabilities to
produce
the phospholipid-rich material, surfactant that lines the respiratory
epithelium.

2. Metabolic and Host Defenses

Handling of the breakdown products of hemoglobin is also a difficult
task for the premature infant. The ability of the immature liver to
conjugate
bilirubin is reduced, the life span of the red blood cell is short, and
the bilirubin load presented to the circulation via the enterohepatic
route
is increased. "Physiologic" jaundice is, therefore, higher in the
preterm
infant and persists for a longer period. Unfortunately, the immature
brain
has an increased susceptibility to the neurotoxic effects of high
levels
of unconjugated bilirubin, and kernicterus can develop in the preterm
baby
at a relatively low level of bilirubin. Other problems affecting the
baby
include the rapid development of hypoglycemia (35 mg%), hypocalcemia
and
hypothermia. Newborns have a poorly developed gluconeogenesis system,
and
depends on glycolysis from liver glycogen stores (depleted 2-3 hrs
after
birth) and enteral nutrition. Immature infants can develop
hyperglycemia
from reduced insulin response to glucose causing intraventricular
hemorrhage
and glycosuria. The preterm and surgical neonate is more prone to
hypocalcemia
due to reduced stores, renal immaturity, and relative
hypoparathyroidism
(high fetal calcium levels). Symptoms are jitteriness and seizures with
increase muscle tone. Calcium maintenance is 50 mg/kg/day. Human beings
are homeothermic organisms because of thermoregulation. This
equilibrium
is maintained by a delicate balance between heat produced and heal
lost.
Heat production mechanisms are: voluntary muscle activity increasing
metabolic
demands, involuntary muscle activity (shivering) and non-shivering
(metabolizing
brown fat). Heat loss occurs from heat flow from center of the body to
the surface and from the surface to the environment by evaporation,
conduction,
convection and radiation. There is an association between hypothermia
and
mortality in the NICU's. The surgical neonate is prone to hypothermia.
Infant produce heat by increasing metabolic activity and using brown
fat.
Below the 35°C the newborn experiences lassitude, depressed
respiration,
bradycardia, metabolic acidosis, hypoglycemia, hyperkalemia, elevated
BUN
and oliguria (neonatal cold injury syndrome). Factors that precipitate
further these problems are: prematurity, prolonged surgery, and
eviscerated
bowel (gastroschisis). Practical considerations to maintain temperature
control are the use of humidified and heated inhalant gases during
anesthesia,
and during all NICU procedures use radiant heater with skin
thermistor-activated
servo-control mechanism. The newborn's host defenses against infection
are generally sufficient to meet the challenge of most moderate
bacterial
insults, but may not be able to meet a major insult. Total complement
activity
is 50% of adults levels. C3,C4,C5 complex, factor B, and properdin
concentration
are also low in comparison to the adult. IgM, since it does not pass
the
placenta, is absent.

3- Surgical Response of Newborns

The endocrine and metabolic response to surgical stress in newborns
(NB) is characterized by catabolic metabolism. An initial elevation in
cathecolamines, cortisol and endorphins upon stimulation by noxious
stimuli
occurs; a defense mechanism of the organism to mobilize stored energy
reserves,
form new ones and start cellular catabolism. Cortisol circadian
responsiveness
during the first week of life is diminished, due to inmaturation of the
adrenal gland. Cortisol is responsible for protein breakdown, release
of
gluconeogenic aminoacids from muscle, and fat lipolysis with release of
fatty acids. Glucagon secretion is increased. Plasma insulin increase
is
a reflex to the hyperglycemic effect, although a resistance to its
anabolic
function is present. During surgical stress NB release glucose, fatty
acids,
ketone bodies, and amino acids; necessary to meet body energy needs in
time of increase metabolic demands. Early postoperative parenteral
nutrition
can result in significant rate of weight gain due to solid tissue and
water
accumulation. Factors correlating with a prolonged catabolic response
during
surgery are: the degree of neuroendocrinological maturation, duration
of
operation, amount of blood loss, type of surgical procedure, extent of
surgical trauma, and associated conditions (hypothermia, prematurity,
etc.).
They could be detrimental due to the NB limited reserves of nutrients,
the high metabolic demands impose by growth, organ maturation and
adaptation
after birth. Anesthetics such as halothane and fentanyl can suppress
such
response in NB.

B. Congenital Torticollis

Congenital muscular torticollis is a disorder characterize by
shortening
of the cervical muscles, most commonly the sternocleidomastoid (SCM)
muscle,
and tilting of the head to the opposite side. This is the result of
endomysial
fibrosis of the SCM muscle. There is a relationship between birth
position
and the side affected by the contracture. Congenital torticollis
causes:
plagiocephaly (a craniofacial deformity), fascial asymmetry
(hemihypoplasia),
scoliosis and atrophy of the ipsilateral trapezius muscle if not
corrected.
Torticollis can develop at any age, although is more common during the
first six months of life. The SCM muscle can be a fibrous mass, or a
palpable
tumor 1-3 cm in diameter within the substance of the muscle is
identified
by two to three weeks of age. Management is conservative in most cases
using early physiotherapy exercises' a mean duration of three months to
achieve full passive neck range of motion. The severity of restriction
of motion is the strongest predictor of treatment duration. Those
children
with failed medical therapy or the development of fascial
hemihypoplasia
should undergo surgical transection of the SCM muscle.

C. Thyroglossal Duct Cysts

Thyroglossal duct cyst (TDC) is the most common congenital anterior
midline
neck mass usually (2/3 of cases) presenting before the second decade of
life. Symptoms appear at an average age of four with the sudden
appearance
of a cystic mass at the angle of neck level moving with tongue
protrusion
and swallowing. Males are more commonly affected than females. TDC is
an
embryologic anomaly arising from epithelial remnant left after descent
of the developing thyroid from the foramen cecum. The lining is
cuboidal,
columnar or pseudostratified epithelium. TDC is associated to
discomfort,
infection and a slight probability of malignancy. A legally protective
requirement is to document that the mass is not ectopic thyroid gland.
Diagnosis is physical. Sonograms will show a cyst between 0.4 and 4 cm
in diameter, with variable sonographic appearance and no correlation
with
pathological findings of infection or inflammation. Once infected
surgical
excision is more difficult and recurrence will increase. Management is
Sistrunk's operation: Excision of cyst with resection of duct along
with
the central portion of hyoid bone (a minimum of 10-15 mm of hyoid bone
should be removed) and some muscle surrounding the proximal ductules
(the
length of single duct above the hyoid bone spreads into many ductuli as
it approach the foramen cecum). Extensive dissection can cause
pharyngodynia.
The greatest opportunity for cure is surgery at initial non-inflamed
presentation.
Inadequate excision is a risk factor for further recurrence.

D. Branchial Cleft Fistulas

Branchial cleft fistulas (BCF) originate from the 1st to 3rd branchial
apparatus during embryogenesis of the head and neck. Anomalies of the
2nd
branchial cleft are by far the most commonly found. They can be a cyst,
a sinus tract or fistulas. Fistulas (or sinus tract if they end
blindly)
display themselves as small cutaneous opening along the anterior lower
third border of the sternocleidomastoid muscle, communicates proximally
with the tonsillar fossae, and can drain saliva or a mucoid secretion.
Management consists of excision since inefficient drainage may lead to
infection. I have found that dissection along the tract (up to the
tonsillar
fossa!) can be safely and easily accomplished after probing the tract
with
a small guide wire in-place. This will prevent injury to nerves,
vessels
and accomplish a pleasantly smaller scar. Occasionally a second
stepladder
incision in the neck will be required. 1st BCF are uncommon, located at
the angle of the mandible, and communicating with the external auditory
canal. They have a close association with the fascial nerve. 3rd BCF
are
very rare, run into the piriform sinus and may be a cause of acute
thyroiditis
or recurrent neck infections.

E. Cystic Hygroma

Cystic hygroma (CH) is an uncommon congenital lesion of the lymphatic
system
appearing as a multilocular fluid filled cavity most commonly in the
back
neck region, occasionally associated with extensive involvement of
airway
or vital structures. The etiology is intrauterine failure of lymphatics
to communicate with the venous system. Prenatal diagnosis can be done
during
the first trimester of pregnancy as a huge neck tumor. Differential
diagnosis
includes teratomas, encephalocele, hemangiomas, etc. There is a strong
correlation between prenatal dx and Turner's syndrome (> 50%),
structural
defects (Noonan's syndrome) and chromosomic anomalies (13, 18, 21).
Early
diagnosis (< 30 wk gestation) is commonly associated to those
anomalies,
non-immune hydrops and dismal outcome (fetal death). Spontaneous
regression
is less likely but can explain webbed neck of Turner and Noonan's
children.
Prenatal dx should be followed by cytogenetic analysis: chorionic
villous
sampling, amniocentesis, or nuchal fluid cell obtained from the CH
itself
to determine fetal karyotype and provide counseling of pregnancy. Late
diagnosis (>30 wks) should be delivered in tertiary center prepare
to deal
with dystocia and postnatal dyspnea of newborn. The airway should be
secured
before cord clamping in huge lesions. Intracystic injection of OK432
(lyophilized
product of Streptococcus pyogenes) caused cystic (hygromas)
lymphangiomas
to become inflamed and led to subsequent cure of the lesion without
side
effects.

Work-up (Logical approach)1. While the infant is being studied, it must be kept in mind that
the problem may be "non-surgical". a. Sepsis of the newborn with associated
ileus is the most important cause of non-surgical bilious vomiting and
abdominal distention. b. Intracranial lesions
i. Hydrocephalus
ii. Subdural hemorrhage c. Renal disease associated with uremia.
i. Renal agenesis
ii. Polycystic disease
iii. Other urinary tract anomalies which may be associated with severe
hydronephrosis.

2. Plain roentgenograms of the abdomen. a. Diagnostic in complete high intestinal
obstruction-
no gas in distal small bowel. i. Double bubble in
duodenal
obstruction. ii. Few gas filled loops
beyond duodenum indicates jejunal atresia. b. Many gas filled loops (requires 24 hours)
indicates some form of low intestinal obstruction. i. Ileal atresia ii. Meconium ileus (an
unfortunate misnomer)- obstruction of the distal small intestine by
thick
undigested meconium. iii. Meconium plug
syndrome
- obstruction of colon by a plug of meconium. iv. Small left colon
syndrome. v. Hirschsprung's disease
- congenital aganglionosis of colon starting with the rectum. vi. Colonic atresia. c. May be nonspecific in instances of malrotation
of the intestines. This diagnosis must always be considered in
neonates
with unexplained bilious vomiting. d. Calcifications - at some time during fetal
life meconium was (is) present in the abdomen.

3. Contrast enema will differentiate the various types of low
intestinal
obstruction. a. Microcolon - complete obstruction of the small
bowel. b. Meconium plug syndrome - colon dilated
proximal
to an intraluminal mass. c. Hirschsprung's disease - although it may
appear
to be diagnostic, not reliable in the newborn. d. Small left colon syndrome - colon dilated
to the splenic flexure, then becomes narrow.

4. Upper G.I. series - the procedure of choice in diagnosing
malrotation
of the intestines. In the past a contrast enema was thought to be the
diagnostic
test of choice in instances of malrotation but the cecum and ascending
colon can be in normal position in an infant or child with malrotation
of the intestines.

5. Rectal biopsy - a pathologist competent in reading the slides
is essential and should not be taken for granted. a. Suction biopsy of the rectal mucosa and
submucosa-
best screening procedure to rule out Hirschsprung's disease (ganglion
cells
are present in the submucosa), and is diagnostic in experienced hands. b. Full thickness biopsy of the rectal wall may
be necessary if the suction biopsy is non-diagnostic or if the
pathologist
is unwilling or unable to make the diagnosis of aganglionosis on a
suction
biopsy specimen. This procedure is difficult in the small infant and
has
been replaced by the suction biopsy in most centers. c. All newborns who have delayed passage of
meconium
associated with a suspicious contrast enema should have a suction
biopsy
of the rectal mucosa and submucosa. With this technique, Hirschsprung's
disease will be diagnosed early before it is complicated with
enterocolitis.
If delayed passage of meconium is "cured" by rectal
stimulation(suppository,
thermometer, or finger), it must be kept in mind that the diagnosis of
Hirschsprung's disease is still a possibility. Whether or not a suction
biopsy of the rectum is done before the infant goes home depends on the
clinical setting but the safe course of action is to do the rectal
biopsy
before discharge. Parents may not call before the infant gets into
trouble
with enterocolitis. d. Suction biopsy of the rectum is probably
indicated
in all cases of so called meconium plug syndrome or small left colon
syndrome.
If the suction biopsy is not done, the infant must be observed for
recurrent
gastrointestinal symptoms. A breast-fed infant who has Hirschsprung's
disease
can "get by" for a prolonged period of time.

6. Concluding comments: The newborn suspected of having intestinal
obstruction
should be studied in a logical step by step manner. It is important
that
it be definitely established that the infant has a surgical problem
before
surgery is performed. This is usually not difficult in instances of
complete
high small bowel obstruction or when plain films of the abdomen show
calcification
and/or a distal small bowel obstruction with the contrast enema showing
a microcolon or a definite malrotation of the colon (cecum in upper
mid-abdomen
or left upper quadrant). When plain films are suggestive of a high small
bowel obstruction but there is gas in the distal small bowel, an upper
GI series rather than a contrast enema should be performed. It is
critically
important that the diagnosis of malrotation of the intestines be always
considered and ruled out in a neonate with bilious vomiting. Prompt
recognition
and treatment of malrotation of the intestines which is often
associated
with a midgut volvulus avoids the dire consequences of the problems
associated
with a massive small bowel resection. Mistakes are frequently made when the contrast
enema is interpreted as normal, meconium plug syndrome, small left
colon
syndrome or Hirschsprung's disease. In all of these clinical
situations,
a suction biopsy of the rectum is an excellent screening
procedure.
If ganglion cells are present, Hirschsprung's disease is ruled out and
the infant probably has a non-surgical diagnosis. If ganglion
cells
are absent, the next step depends on the clinical picture and setting.
If
the pathologist is experienced and confident of the interpretation, the
diagnosis of Hirschsprung's disease can be made with confidence. If
there
is any doubt about the absence of ganglion cells in the suction biopsy,
a full thickness biopsy of the rectum (a difficult technical procedure
requiring a general anesthetic) can be done to settle the issue. If
Hirschsprung's
disease is believed to be the problem, it must be diagnosed
histologically
before the infant is operated upon because at the time of surgery the
site
of obstruction may not be apparent and the abdomen may be closed
because
no obvious site of obstruction is found. Hypothyroidism in the first two to three months
of life can mimic Hirschsprung's disease in all aspects except for a
normal
rectal biopsy. Another important point to remember is that
duodenal
atresia is a different disease from jejunal or ileal atresia in terms
of
their cause. Jejunal and ileal atresia occur as a result of a vascular
accident in the small bowel mesentery during fetal life. Consequently,
there is a relatively low incidence of other congenital anomalies
except
for cystic fibrosis. Duodenal atresia is a different disease in that
there is a very high incidence of associated anomalies-- (Down's
syndrome,
imperforate anus, renal anomalies, congenital heart disease, etc.). Malrotation of the intestines and
Hirschsprung’s
disease must be ruled out before a newborn with unexplained bilious
vomiting
and/or abdominal distention is sent home. It can be unsafe to rely on
parents
to observe their infant for problems resulting from the above
conditions.
If diagnosed late, malrotation of the intestines or
Hirschsprung’s
disease
can become life threatening or result in life long problems.

Esophageal atresia (EA) with distal tracheo-esophageal fistula
(TEF)
is the most common congenitalanomaly of the esophagus, followed by EA without TEF also known
as pure esophageal atresia andpure TEF. Incidence is one in every 2500 live births. The trachea
and esophagus initially begin as a ventral diverticulum of the foregut
during the third intrauterine week of life. A proliferation of
endodermal
cells appears on the lateral aspect of this growing diverticulum. These
cell masses will divide the foregut into trachea and esophageal tubes.
Whether interruption of this normal event leads to tracheo-esophageal
anomalies,
or during tracheal growth atresia of the esophagus results because of
fistulous
fixation of the esophagus to the trachea remians to be proven.
Polyhydramnios
is most commonly seen in pure EA. EA causes excessive salivation,
choking,
coughing, regurgitation with first feed and inability to pass a feeding
tube into the stomach. Contrast studies are rarely needed and of
potential
disaster (aspiration). Correct dehydration, acid-base disturbances,
respiratory
distress and decompress proximal esophageal pouch (Reploge tube).
Evaluate
for associated conditions such as VACTERL association. Correct
dehydration,
acid-base disturbances, respiratory distress and decompress proximal
esophageal
pouch (Reploge tube). Evaluate for associated conditions such as
VACTERL
association (3 or more): -Vertebral anomalies i.e. hemivertebrae, spina bifida -Anal malformations i.e. imperforate anus -Cardiac malformations i.e. VSD, ASD, Tetralogy Fallot -Tracheo-Esophageal fistula (must be one of the associated
conditions) -Renal deformities i.e. absent kidney, hypospadia, etc. -Limb dysplasia Early surgical repair (transpleural or
extrapleural)
is undertaken for those babies with adequate arterial blood gases,
adequate
weight (>1200 gm) and no significant associated anomalies. Delayed
repair
(gastrostomy first) for all other patients. Repair consists of
muscle-sparing
thoracotomy, closure of TEF and primary anastomosis. Esophagogram is
done
7-10 days after repair. Most important predictors of outcome: birth
weight,
severity of pulmonary dysfuntion, and presence of major congenital
cardiac
disease. Complications after surgery: anastomotic leak, stricture,
gastroesophageal
reflux, tracheomalacia and recurrent TEF. Increase survival is
associated
with improvements in perioperative care, meticulous surgical technique
and aggressive treatment of associated anomalies. Congenital isolated tracheo-esophageal fistula
(TEF) occurs as 4-6% of the disorders of the esophagus bringing
problems
during early diagnosis and management. More than H-type is N-type, due
to the obliquity of the fistula from trachea (carina or main bronchi)
to
esophageal side (see the figure) anatomically at the level of the neck
root (C7-T1). Pressure changes between both structure can cause
entrance
of air into the esophagus, or esophageal content into the trachea.
Thus,
the clinical manifestation that we must be aware for early diagnosis
are:
cyanosis, coughing and choking with feedings, recurrent chest
infections,
persistent gastrointestinal distension with air, and hypersalivation.
Diagnosis
is confirmed with a well-done esophagogram, or video-esophagogram (high
success rates, establish level of the TEF). Barium in the trachea could
be caused by aspiration during the procedure. Upon radiologic doubt
bronchoscopy
should be the next diagnostic step. Any delay in surgery is generally
due
to delay in diagnosis rather than delay in presentation. Management
consists
of surgical closure of the TEF through a right cervical approach. Hint:
a small guide-wire threaded through the fistula during bronchoscopy may
be of some help. Working in the tracheo-esophageal groove can cause
injury
to the recurrent laryngeal nerve with vocal cord paralysis. Recurrence
after closure is rare.aggressive treatment of associated anomalies. The three most common anastomotic complications
are in order of frequency: stricture, leakage and recurrent TEF.
Recurrent
TEF after surgical repair for esophageal atresia occurs in
approximately
3-15% of cases. Tension on the anastomoses followed by leakage may lead
to local inflammation with breakage of both suture lines enhancing the
chance of recurrent TEF. Once established, the fistula allows saliva
and
food into the trachea, hence clinical suspicion of this diagnosis
arises
with recurrent respiratory symptoms associated with feedings after
repair
of esophageal atresia. Diagnosis is confirmed with cineradiography of
the
esophagus or bronchoscopy. A second thoracotomy is very hazardous, but
has proved to be the most effective method to close the recurrent TEF.
Either a pleural or pericardial flap will effectively isolate the
suture
line. Pericardial flap is easier to mobilize, provides sufficient
tissue
to use and serves as template for ingrowth of new mucosa should leakage
occur. Other alternatives are endoscopic diathermy obliteration, laser
coagulation, or fibrin glue deposition.

B. Gastro-Duodenal Anomalies

B.1 Gastric Anomalies

Congenital gastric outlet obstruction is extremely rare. It
occurs
either in the pyloric or antral region. Antral membranes (web or
diaphragm)
are thin, soft and pliable, composed of mucosa/submucosa, and located
eccentric
1-3 cm proximal to pyloro-duodenal junction. They probably represent
the
developmental product of excess local endodermal proliferation and
redundancy.
The diagnosis should rely on history, contrast roentgenology studies
and
endoscopic findings. Symptoms are those of recurrent non-bilious
vomiting
and vary according to the diameter of aperture of the membrane. There
is
a slight male predominance with fair distribution between age groups in
children. Associated conditions: pyloric stenosis, peptic ulcer and
cardiac.
History of polyhydramnios in the mother. Demonstration of a
radioluscent
line perpendicular to the long axis of the antrum is diagnostic of a
web.
Endoscopy corroborates the diagnosis. Management can be either surgical
or non-surgical. Surgical Tx is successful in symptomatic pt. and
consist
of pyloroplasty with incision or excision of the membrane. Other
alternative
is endoscopic balloon dilatation or transection of the web.
Non-obtructive
webs found incidentally can be managed medically with small curd
formula
and antispasmodics. The presence of an abnormally dilated gastric
bubble
in prenatal sonography should alert the physician toward the diagnosis
of congenital antro-pyloric obstruction.

B.2 Pyloric Stenosis

Is an abnormality of the pyloric musculature (hypertrophy)
causing
gastric outlet obstruction in early infancy. The incidence is 3 per
1000
live births. The etiology is unknown, but pylorospasm to formula
protein
cause a work hypertrophy of the muscle. Diagnostic characteristics are:
non-bilious projectile vomiting classically 3-6 weeks of age, palpable
pyloric muscle "olive", contrast studies are not necessary when the
pyloric
muscle is palpated, enlarged width and length in ultrasonography.
The treatment consist in correction of hypochloremic alkalosis and
state
of dehydration and performing a Fredet-Ramstedt modified pyloromyotomy.
Post-operative management consist of: 50% will have one to several
episodes
of vomiting, usually can feed and go home in 24-36 hours, initial feeds
start 8-12 hours after surgery.

B.3 Duodenal Malformations

Can be intrinsic (Atresia, Stenosis, Webs) or extrinsic (Annular
pancreas, Ladd's bands). Occur distal or proximal to the ampulla of
Vater.
Most commonly distal to ampulla and therefore bilious vomiting is
present.
(Note: Bilious vomiting is surgical until proven otherwise in a baby). "Windsock" webs have clinical importance because of their
tendency to be confused with distal duodenal obstruction and because of
the frequent occurrence of an anomalous biliary duct entering along
their
medial margin. Embryology: The first major event in the
differentiation
of the duodenum, hepatobiliary tree, and pancreas occurs at about the
third
week in gestation, when the biliary and pancreatic buds form at the
junction
of the foregut and the midgut. The duodenum at this time is a solid
cord
of epithelium, which undergoes vacuolization followed by recanalization
and restitution of the intestinal lumen over 3-4 weeks of normal
development.
Failure of recanalization of the second part of the duodenum results in
congenital obstruction of the lumen, often in conjunction with
developmental
malformation of the pancreatic anlagen and the terminal part of the
biliary
tree. In support of this concept is the high incidence of annular
pancreas
observed, believed to represent a persistence of the ventral pancreatic
anlage in association with intrinsic duodenal obstruction.Congenital partial obstruction of the duodenum can be either
intrinsic
(membrane, web or pure) orextrinsic (Ladd's bands, annular pancreas). A significant group
(25-33%) is born with Down's syndrome.This does not entail a higher risk of early mortality unless
associated
with cardiac malformations. Otherassociated conditions are malrotation (midgut volvulus is rare due
to absent bowel distension andperistalsis), biliary tract anomalies and Meckel's diverticulum.
The diagnosis is suggested in utero bythe double-bubble image on ultrasound. Vomiting is the most frequent
presenting symptom. UGIS isdiagnostic, showing a dilated stomach and first duodenal portion
with scanty passage of contrastmaterial distally. Management varies accordingly to the type of
stenosis: Ladd's bands are lysed. Purestenosis is opened longitudinally and closed transversely
(Heineke-Mickulicz).
Membranous stenosis isresected. Successful endoscopic membranectomy of duodenal stenosis
has been reported.Duodeno-duodenostomy is the procedure of choice for annular
pancreas.
Diaphragms can rarely bedouble. Anastomotic malfunction requiring prolonged intravenous
nutrition and hospitalization hasprompted development of a diamond shape larger stoma. Tapering or
plication of the dilated duodenumis another effective method of improving disturbed transit. Other
complications after surgery aremegaduodenum with blind loop syndrome, biliary reflux, cholestatic
jaundice, delayed transit and bowelobstruction. Early mortality is associated to prematurity and
associated
malformations. Long-termfollow-up is warranted to identify late problems. The diagnostic characteristics are: bilious vomiting, history
of polyhydramnios in mother, KUB with classic "Double-bubble"
appearance,
a microcolon in barium enema study or malrotation. Treatment consist in: (1) duodeno-duodenostomy bypass for
atresias, annular pancreas, and some stenosis. (2) duodenoplasty for
webs,
and stenosis, and (3) lysis of ladd's bands and Ladd's procedure for
malrotation.
Associated anomalies are: Down's syndrome (20-30%), VACTERL syndrome,
CNS
anomalies and cardiac anomalies.

C. Malrotation and Volvulus

The rotation and normal fixation of the intestinal tract takes
place
within the first three months of fetal life. In the earliest stages
when
the intestinal tract is recognizable as a continuous tube, the stomach,
small intestine, and colon constitute a single tube with its blood
supply
arising posteriorly. The midgut portion of this tube, from the second
portion
of the duodenum to the mid-transverse colon, lengthens and migrates out
into an extension of the abdomen, which lies at the base of the
umbilical
cord. Here this loop of bowel undergoes a 270-degree counterclockwise
twist
at its neck. In the center of the twisted loop lie the blood vessels
that
will become the superior mesenteric artery and vein. After rotation,
the
small intestine quite rapidly withdraws into the abdominal cavity, with
the duodenum and the proximal jejunum going first. During this process
the duodenojejunal junction goes beneath and to the left of the base of
the superior mesenteric vessels. This leaves the upper intestine,
including
the stomach and the duodenum, encircling the superior mesenteric
vessels
like a horseshoe with its opening on the left side of the embryo. The
small
intestine then follows into the abdomen, and withdrawal of the right
half
of the colon takes place so that it lies to the left. At the next step,
the cecum and the right colon begin to travel across the top of the
superior
mesenteric vessels and then down to the right lower quadrant. The colon
now lies draped across the top of the superior mesenteric vessels,
again
like a horseshoe, with its opening placed inferiorly. The
duodenojejunal
loop is said to attach to the posterior abdominal wall soon after its
turn,
whereas the mesenteric attachments of the entire colon and of the
remaining
small bowel gradually adhere after they arrive in their normal
positions.
In malrotation the right colon can create peritoneal attachments that
include
and obstruct the third portion of the duodenum (Ladd's bands). The diagnostic hallmarks are: bilious vomiting (the deadly
vomit), abdominal distension and metabolic acidosis. A UGIS is more
reliable
than barium enema, most patients present in first month of life
(neonatal),
but may present at any time. The treatment is immediate operation; volvulus often means
strangulation. Needs fluid and electrolyte replacement. Ladd's
procedure
consist of: reduce volvulus with a counterclockwise rotation, place
small
bowel in right abdomen, lysed ladd's bands, place large bowel in left
abdomen,
do an appendectomy. In cases of questionable non-viable bowel a second
look procedure is required.

D. Intestinal Atresias

Intestinal atresias are the product of a late intrauterine
mesenteric
vascular accident (blood supply was not received by a portion of bowel)
as attested by Louw and Barnard in 1955. They are equally distributed
from
the ligament of treitz to the ileocecal junction. Colonic atresias are
very rare. There is proximal bowel dilatation, with distal (unused)
micro-bowel.
The diagnosis is suspected with maternal history of polyhydramnios (the
higher the atresia), bilious vomiting, abdominal distension and
obstipation.
KUB shows "thumb-size" dilated bowel loops, and barium enema a
microcolon
of disuse. Louw classified them into: Type I: an intraluminal diaphragm
with seromuscular continuity. Type II: cord-like segment between the
bowel
blinds ends. Type IIIA: atresia with complete separation of blind ends
and V-shaped mesenteric defect (see figure), the most commonly found.
Type
IIIB: jejunal atresia with extensive mesenteric defect and distal ileum
acquiring its blood supply entirely from a single ileocolic artery. The
distal bowel coils itself around the vessel, giving the appearance of
an
"apple peel"deformity. Type IV: multiple atresias of the small
intestine.
After preoperative stabilization (GI decompression, electrolytes
disturbances'
correction, antibiotherapy, and normothermia), treatment consists of
exploratory
laparotomy, resection of proximal dilated intestine, and end to oblique
anastomosis in distal jejuno-ileal atresias. Tapering jejunoplasty with
anastomosis is preferred in proximal defects.

Meconium ileus is a neonatal intraluminal intestinal obstruction
caused by inspissated meconium blocking the distal ileum. Occurs in
10-15%
of all patients with cystic fibrosis, and 85-95% of patients with
meconium
ileus have cystic fibrosis. The meconium has a reduced water, abnormal
high protein and mucoproteint content, the result of decreased
pancreatic
enzyme activity and prolonged small bowel intestinal transit time.
Meconium
Ileus is classified into two types: (1) Simple meconium ileus: The
distal
small bowel (10-30 cm of distal ileum) is relatively small, measuring
less
than 2 cm in diameter and contains concretions of gray, inspissated
meconium
with the consistency of thick glue or putty. It is often beaklike in
appearance,
conforming to the shape of the contained pellets. Proximally, the
mid-ileum
is large, measuring up to 7 cm in diameter. It is greatly distended by
a mass of extremely thick, tenacious, dark green or tarry meconium. The
unused small colon (microcolon) contains a small amount of inspissated
mucus or grayish meconium. (2) Complicated meconium ileus: usually
occurs
during the prenatal period associated to volvulus, atresias, gangrene,
perforation or peritonitis. A cystic mass or atresia of the bowel may
occur.
The degree of obstruction varies, may be cured in mild cases by rectal
irrigations. Failure to pass meconium, abdominal distension and
vomiting
are seen in more severe cases. The diagnosis is suspected with findings
of: multiple loops of dilated small bowel and coarse granular
"soap-bubble"
appearance on plain abdominal films. Some cases may show calcifications
in the peritoneum (Meconium peritonitis). The Sweat Test is diagnostic
of cystic fibrosis (value over 60 meq/L of sweat sodium or chloride are
diagnostic). This test is not useful in infant during first weeks of
life.
Therapy is either: (1) Nonoperative- should be tried first. It consist
of a careful gastrograffin enema after the baby is well-hydrated.
Gastrograffin
is a hyperosmolar aqueous solution of meglumine diatrizoate containing
0.1% polysorbate-80 (tween-80, a wetting agent) and 37% iodine. Its
success
is due to the high osmolarity (1700 mosm/liter) which draws fluid into
the bowel and softens and loosens the meconium. (2) Surgical therapy
that
has included: ileostomy with irrigation, resection with anastomosis,
and
resection with ileostomy (Mikulicz, Bishop-Koop, and Santulli).
Post-operative
management includes: 10% acetylcysteine p.o., oral feedings
(pregestimil),
pancreatic enzyme replacement, and prophylactic pulmonary therapy.
Long-term
prognosis depends on the degree of severity and progression of cystic
fibrosis
pulmonary disease.

Hirschsprung's is the congenital
absence of
parasympathetic innervation of the distal intestine. The colon proximal
to the aganglionic segment, in an effort to overcome the partial
obstruction,
becomes distended and its wall markedly thickened because of muscle
hypertrophy.
Occurs 1 in 1000-1500 live births with a 4:1 male predominance. 96% are
TAGA. 4% prematures.

The parasympathetic ganglion cell network
located
between the circular and longitudinal muscle layers is referred to as
Auerbach's
plexus, whereas Meissner's plexus is the submucosal layer of ganglion
cells
just beneath the muscularis mucosa. In Hirschsprung's disease, ganglion
cells are absent from all layers. That aganglionic segment usually
involves
the terminal intestine, i.e. the rectum or rectosigmoid. The
aganglionic
segment may, however, include the entire large bowel and even small
bowel.

Hirschsprung's disease (HD) is
characterized by
lack
of enteric ganglion cells, hyperplasia of abnormal nerve fibers and a
non-propulsive,
non-relaxing segment of bowel. Classically the etiology is attributed
to
a failure of cranio-caudal migration of parasympathetic neural crest
cells
to the distal bowel. A plausible explanation for the failure of
relaxation
of the bowel involved is a deficiency of enteric inhibitory nerves that
mediates the relaxation phase of peristalsis. This nerves are intrinsic
to the gut and are classify as non-adrenergic and non-cholinergic.
Nitric
oxide (NO) has recently been implicated as the neurotransmitter which
mediates
the relaxation of smooth muscle of the GI tract in HD. It's absence in
aganglionic bowel might account for the failure of relaxation during
peristalsis.
Besides, adhesions molecules (absent in aganglionic bowel) during early
embryogenesis might restrict the neuro-ectodermal origin involved in
the
initial contact between nerves and muscle cell (synaptogenesis)
suggesting
that developmental anomaly of innervated muscle and absent NO causes
the
spasticity characteristic of HD.

Symptoms usually begin at birth, frequently
with
delayed passage of meconium. Any newborn who fails to pass meconium in
the first 24-48 hours of life should be evaluated for possible
Hirschsprung's
disease. In some infants, the presentation is that of complete
intestinal
obstruction. Others have relatively few symptoms until several weeks of
age, when the classic symptom of constipation has its onset. Diarrhea
is
not uncommon but differs from the usual infantile diarrhea in that it
is
associated with abdominal distension. Occasionally the patient will go
many years with mild constipation and diagnosis will be delayed.

The diagnosis is first suspected based on
history
and physical examinations (characteristically there is no stool in
rectum
and abdominal distension is painless). Initial evaluation includes an
unprepped
barium enema (the first enema should be a barium enema!). The
aganglionic
rectum appears of normal caliber or spastic, there is a transition zone
and then dilated colon proximal to the aganglionic segment. 24-hrs
delayed
films shows poor emptying with barium throughout the colon, as opposed
to the child with psychogenic stool holding in whom the barium
generally
collects in the distal rectosigmoid. Rectal suction biopsy is then
performed.
This can be done without anesthesia and the submucosal plexus is
examined
for ganglion cells. With experience, a good pathologist (should be an
expert!),
can identify the presence or absence of ganglion cells in this specimen
without a full thickness biopsy. Difficulty in interpreting the
specimen
or not enough to include several slides of submucosa would require a
full-thickness
biopsy for definitive diagnosis generally done under general
anesthesia.
Some centers employ manometry, histochemical studies or special stains
for diagnosis. These special studies are only as good as the person
performing
them and interpreting the results.

The initial treatment requires performing a
"leveling"
colostomy in the most distal colon with ganglion cells present. This
requires
exploration with multiple seromuscular biopsies of the colon wall to
determine
the exact extend of the aganglionosis. The colostomy is placed above
the
transition zone. Placement of the colostomy in an area of aganglionosis
will lead to persistent obstruction. Once the child has reached an
adequate
size and age (6-12 months; 20 pounds or more), a formal pull-through
procedure
is done. Some of this are: Swenson, Duhamel and Soave procedures.
Current
preference is for Soave procedure (modified endorectal pull-through)
and
consist of resection of the majority of aganglionic bowel except for
the
most distal rectum, the mucosa and submucosa of this rectum is excised
and the normally innervated proximal bowel is pulled through the
seromuscular
coat of retained rectum and suture immediately above the dentate line.
Recently a laparoscopic procedure without colostomy use is being done
earlier
in life with promising results.

Total colonic aganglionosis (TCA) is found in
approx. 2 to 13% of patients with Hirschsprung's disease (2). There are
three critical phases for patients with TCA (15). The first period comprises the time from birth until correct
diagnosis. Patients with TCA present with a large variety of symptoms.
Several authors have outlined the diagnostic problems in patients with
TCA (2,4,18). Atypical symptoms may lead to excessively delayed
diagnosis.
Festen et al. report a delay in diagnosis up to 160 days after birth
(4).
Patients present with either ileus or symptoms as in typical
Hirschsprung's
disease but additionally with recurrent vomiting. In patients
presenting
with ileus, diagnosis may be delayed for several weeks because
causative
factors like volvulus or meconium ileus do not primarily warrant
investigations
for aganglionosis. Furthermore, TCA may be associated with other
anomalies
of the gastrointestinal tract. Only a few reports of TCA associated
with
small bowel atresia and volvulus can be found (3, 7). Lally et al.
report
anastomotic failure following repair of ileal atresia due to underlying
extensive aganglionosis (11). In cases of midgut volvulus without
malrotation,
aganglionosis has to be ruled out. Stringer et al. recently published a
series of seven full-term infants with meconium ileus due to extensive
intestinal aganglionosis (18). Neonatal appendicitis, a very rare
disease,
may be the leading symptom of TCA. Therefore, rectal biopsies are
mandatory
in those cases. Ratta et al. state that lack of awareness of the
condition
may lead to delay in diagnosis and inappropriate treatment (15).
Additional
to the diagnostic problems due to atypical and heterogenic symptoms,
histochemical
examination of rectal biopsies may prove negative or equivocal because
increased acetylcholinesterase activity may not be present in TCA
(5,10,12).
Furthermore, there is no typical radiographic pattern (13,17). Plain
abdominal
radiographs usually suggests low bowel obstruction whereas barium enema
usually does not show pathognomonic features. If no mechanical obstruction is found at laparotomy in
neonates
presenting with ileus, it is suggested to resect the appendix to rule
out
TCA. If rectal mucosal biopsies are negative or equivocal, biopsies
should
be repeated or a formal sphincterectomy for thorough analysis is done. The second period lasts from the raising of stoma to its
closure,
including the definite surgical procedure. Failure to thrive and
excessive
fluid losses have been reported in patients with ileostomies (2).
Post-ileostomy
complications, however, have been eliminated after the importance of
oral
sodium supplementation to maintain the enteral co-transport system has
been realized (16). In the series of Cass & Myers, ileostomy
dysfunction
was common with a 20% prolapse rate and 25% rate of persistent
excessive
losses (2). Interestingly, right transversostomies may show a good
function
even in cases of TCA. Therefore, frozen section biopsies are mandatory
when raising a stoma. The definitive surgical procedure has been debated
(2,5,8,9,15).
Colonic patch graft procedures were the first proposals for surgical
management
of TCA (14). The rational behind were to use the distinctive resorptive
function of part of the aganglionic colon (6). Use of the right colon
has
the theoretical advantage of improved water resorption. However the
colon
patch procedures have significant complications, e.g., enterocolitis,
ulceration
of the aganglionic pouch, perforations and extreme dilatation. Multiple
modifications of the technique have been reported but none were
superior
(1,8,9,18). Actually, a modified Duhamel's pull-through procedure seems
favorable in the treatment of TCA (2,15). The third critical phase begins with closure of the stoma.
Complications in this period are predominantly recurrent episodes of
sub-ileus
and diarrhea or nocturnal incontinence. The cause for sub-ileus is a
raised
tone in the residual sphincter. Repeated manual anal dilatations may be
mandatory. The treatment of diarrhea may be managed by diets and/or
Loperamide
often in large doses. Side effects of large doses of Loperamide are
mental
irritability and dyskinesia. Significantly better survival of the patients with TCA
nowadays
is mainly attributed to more accurate diagnosis and improved management
of infants with ileostomies.

Imperforate
anus (IA) is a congenital anomaly in which the natural anal opening is
absent. Diagnosis of IA is usually made shortly after birth on routine
physical examination. The incidence of IA is approximately 1 in
4000-5000
live births and it is more common in males. Its etiology is unknown and
it runs equally through all racial, cultural and socio-economic groups.
There is preliminary evidence (> 5 case reports) of the existence of
autosomal
inheritance (both dominant and recessive) in patients with anorectal
malformations.
IA is classified as either "high" or "low" depending on the termination
of the distal rectum. When the rectum ends above the levator muscles
the
malformations are classified as high, and when the rectum ends below
the
levator muscles the malformations are classified as low. High lesions
are
more frequent in males, low ones in females. Determination of the level
of the lesion (by abdominal x-ray or perineal ultrasound) is critical
for
appropriate management. Children who have IA may also have other
congenital
anomalies. The acronym VACTERL describes the associated problems that
infants
with IA may have: Vertebral defects, Anal atresia, Cardiac anomalies,
Tracheoesophageal
fistula,
Esophageal atresia, Renal anomalies, and Limb anomalies.
Repair of low IA is relatively simple and is usually treated with
perineal
anoplasty; however, repair of high IA is more complex. Patients are
initially
given a temporary colostomy and time is given to allow the child to
grow.
A pull-through operation is completed at a later date. Independent of
the
level of the lesion, the goal of the surgery is the creation of
adequate
nerve and muscle structures around the rectum and anus to provide the
child
with the capacity for bowel control.
MALES: most important decision in the initial management of Imperforate
Anus (IA) male patient during the neonatal period is whether the baby
needs
a colostomy and/or another kind of urinary diversion procedure to
prevent sepsis or metabolic derangements. Male patients will benefit
from
perineal inspection to check for the presence of a fistula (wait 16-24
hours of life before deciding). During this time start antibiotherapy,
decompress the GI tract, do a urinalysis to check for meconium cells,
and
an ultrasound of abdomen to identify urological associated
anomalies.
Perineal signs in low malformations that will NOT need a colostomy are:
meconium in perineum, bucket-handle defect, anal membrane and anal
stenosis.
These infants can be managed with a perineal anoplasty during the
neonatal
period with an excellent prognosis. Meconium in urine shows the pt has
a fistula between the rectum and the urinary tract. Flat "bottom" or
perineum
(lack of intergluteal fold), and absence of anal dimple indicates poor
muscles and a rather high malformation needing a colostomy. Patients
with
no clinical signs at 24 hours of birth will need a invertogram or
cross-table
lateral film in prone position to decide rectal pouch position. Bowel
>
1 cm from skin level will need a colostomy, and bowel < 1 cm from
skin
can be approach perineally. Those cases with high defect are initially
managed with a totally diverting colostomy. Diverting the fecal stream
reduces the chances of genito-urinary tract contamination and future
damage.
FEMALES: most frequent defect in females patient with imperforate anus
(IA) is vestibular fistula, followed by vaginal fistulas. In more than
90% of females cases perineal inspection will confirm the
diagnosis.
These infants require a colostomy before final corrective surgery. The
colostomy can be done electively before discharge from the nursery
while
the GI tract is decompressed by dilatation of the fistulous tract. A
single
orifice is diagnostic of a persistent cloacal defect usually accompany
with a small-looking genitalia. Cloacas are associated to distended
vaginas
(hydrocolpos) and urologic malformations. This makes a sonogram of
abdomen
very important in the initial management of these babies for screening
of obstructive uropathy (hydronephrosis and hydroureter). Hydrocolpos
can
cause compressive obstruction of the bladder trigone and interfere with
ureteral drainage. Failure to gain weight and frequents episodes of
urinary
tract infections shows a poorly drained urologic system. A colostomy in
cloacas is indicated. 10% of babies will not pass meconium and
will
develop progressive abdominal distension. Radiological evaluation will
be of help along with a diverting colostomy in this cases. Perineal
fistulas
can be managed with cutback without colostomy during the neonatal
period.
The most important prognostic characteristic is the severity of the IA.
Patients with low IA have a good probability of having normal stool
patterns.
Patients with high IA report more problems such as fecal incontinence
and
constipation. For patients who cannot maintain normal bowel function,
the
use of a special diet, underpants liners, enemas and drugs have
ameliorated
their lives. Long-term follow up (with both qualitative and
quantitative
quality of life considerations) of these patients is very important. In
addition, the use of anal endosonography and/or manometry can be used
as
objective measurements of anorectal pressure and sphincter function.

H. Duplications

Duplications of the gastrointestinal tract are considered uncommon
congenital
anomalies usually diagnosed or unexpectedly encountered
intraoperatively
during the first two years of life. The duplicated bowel can occur
anywhere
in the GI tract, is attached to the mesenteric border of the native
bowel,
shares a common wall and blood supply, coated with smooth muscle, and
the
epithelial lining is GI mucosa. May contain ectopic gastric or
pancreatic
tissue. Most are saccular, other tubular. Theories on their origin
(split
notochord syndrome, twining, faulty solid-stage recanalization) do not
explain all cases of duplicated bowel. Three-fourth are found in the
abdomen
(most commonly the ileum and jejunum), 20% in the thorax, the rest
thoraco-abdominal
or cervical. Symptoms vary according to the size and location of the
duplication.
Clinical manifestations can range from intestinal obstruction,
abdominal
pain, GI bleeding, ulceration, or mediastinal compression. Ultrasound
confirms
the cystic nature of the lesion (muscular rim sign) and CT the
relationship
to surrounding structures. Management consist of surgical excision
avoiding
massive loss of normal bowel and removing all bowel suspect of
harboring
ectopic gastric mucosa.

Although intussusception can occur at
any
age, the greatest incidence occurs in infants between 4-10 months of
age.
Over half of the cases are in the first year of life. Frequently occurs
after a recent upper respiratory infection, by Adenovirus type 3 that
causes
a reactive lymphoid hyperplasia that act as lead point (of Peyer's
patch). A definite lead point is identified in
about 5% of patients. These include: Meckel's diverticulum, polyps,
Henoch's
Schonlein purpura, hematoma, lymphoma, foreign bodies, and
duplications.
Most children have no lead point and it is felt that enlarged
mesenteric
nodes or swollen Peyer's patches may be the cause. The baby has
intermittent
periods of severe discomfort with screaming, stiffening and drawing up
of the legs, followed by periods of rest. Vomiting may occur and
bloody,
mucoid (currant jelly) stool may be passed. The baby may become
dehydrated
and appear acutely ill. Frequently, lethargy may be an early sign. The
diagnosis is made by barium enema, and hydrostatic reduction of the
intussusception
with barium is successful in approximately 50% of cases. To be
successful,
the barium must reflux into the terminal ileum. The surgeon should be
notified
before an attempt at barium reduction, and should be present at the
time
of study. Recently the use of gas enema reduction has been successful
in
patients with: (1) symptoms less than 12 hours, (2) no rectal bleeding,
(3) absence of small bowel obstruction, and (4) normally hydrated.
Ultrasonography
can be used as a rapid sensitive screening procedure in the initial
diagnosis
of intussusception. Previous adverse clinical features that precluded
barium
reduction can be replaced during gas reduction. Predictors of failure
of
reduction are: (1) ileocolic intussusception, (2) long duration of
symptoms,
(3) rectal bleeding, and (4) failed reduction at another institution.
Air
reduction (pneumocolon) is a very effective alternative method since it
brings less radiation (shorter flouroscopy time), less costs and less
morbidity
in cases of perforations. Failure of hydrostatic reduction requires
urgent operation through a right lower quadrant horizontal incision.
The
intussusception is reduced by pushing on the distal bowel like a tube
of
toothpaste rather than pulling the proximal bowel. Most cases are
ileo-colic
intussusception, and a few are jejuno-jejunal or ileo-ileal
intussusception. The traditional method of diagnosing and managing
ileo-colic intussusception is barium enema contrast reduction. In China
where this is the most common surgical emergency in childhood,
pneumatic
reduction has been used for more than 25 years. A recent tendency
toward
this approach is seen in recent years in Occident. This consist of
rectal
insufflation of oxygen at a flow rate of 2 L/min, controlling pressure
by adjusting the height of the mercury column, and using maximal
pressures
of 80 mm Hg. Small bowel aeration is a sign of complete reduction.
Series
are successful in 70-90% of cases. Gas enema reduction is very
successful
in patients with: (1) symptoms less than 12 hours, (2) no rectalbleeding, (3) absence of small bowel obstruction, and (4) normally
hydrated. Ultrasonography can beused as a rapid sensitive screening procedure in the initial
diagnosis
of intussusception. Previousadverse clinical features that precluded barium reduction can be
replaced during gas reduction.Predictors of failure of reduction are: (1) ileocolic
intussusception,
(2) long duration of symptoms, (3)rectal bleeding, and (4) failed reduction at another institution.
Air reduction (pneumocolon) is a veryeffective alternative method since it brings less radiation (shorter
flouroscopy time), less costs and lessmorbidity in cases of perforations.

The most common cause of emergency laparotomies in all age
groups,
acute
appendicitis remains a diagnostic challenge, with high perforation
rates
at laparotomy, and, curiously, high negative laparotomy rates. With
current
standard approach and use of antimicrobial medication the overall
mortality
is almost zero, and major complications are gradually declining.

ETIOLOGY

Appendiceal lumen obstruction by a fecalith, lymphoid
hyperplasia,
carcinoid
tumor, anomalous vessels, or intestinal parasites as Ascaris
lumbricoides
leads to acute increase in intraluminal pressure with consequent
ischemia
and mucosal damage. In association with bacterial proliferation this
may
lead to gangrene and perforation.

DIAGNOSIS

Early diagnosis is the key for success in management of
appendicitis,
and it is based solely upon history and physical findings. Image and
laboratory
studies are of relative value.

Signs and Symptoms

Abdominal pain is the chief complaint of appendicitis. It is
usually
periumbilical at onset, colicky due to lumen obstruction and distension
(visceral referred pain), and in a few hours shifts its location to the
RLQ changing to a continuous and intense pattern, explained by parietal
irritation caused by the inflamed appendix exudate. Special concern
must
be given to patients with initial periumbilical pain who localize it
into
uncommon sites. One must always remember that the localized pain in
appendicitis
is directly related to where it lays, so we can have flank or back pain
in retrocecal appendicitis, dysuria in retro vesical cases, etc.
Vomiting,
generally after the pain, is usually present in appendicitis. Bowel
habits
are generally unchanged in early cases, but diarrhea can be present
initially
in up to 10% of cases, usually associated to pelvic appendicitis.

Physical Examination

Simple examination can predict appendicitis when we see the
child
walking,
bent over his right hip, and stepping carefully to avoid minimum
shaking.
The apprehensive little patient lies on the examining table in a supine
position, with a slight flexion of the right leg. When asked to show
the
pain site, he points out with a finger. Abdominal examination should be
done gently, divided in quadrants, and beginning distant from the site
of complaint. It always helps if the patient is asked to help in the
examination,
the surgeon palpating over his hand, to reduce voluntary guarding.
Point
tenderness and/or appendiceal masses at RLQ are diagnostic, but
unfortunately,
they are not present in a great deal of cases. Peritoneal irritation
signs
can be assessed without performing the classic, Blumberg maneuver, just
by soft right heel percussion, or gentle Mc Burney's point finger
percussion.
In advanced cases with "wooden abdomen" and clear infectious signs, the
diagnosis is obvious.

Image and Laboratory

Image resources are poor in diagnosing appendicitis. Plain
abdominal
films can show a fecalith (20%), a dilated and fixed ileal loop
(sentinel
loop) and indirect signs such as scoliosis, psoas line and/or
pre-peritoneal
line blurring. Ultrasound, very good to assess collections, has gained
popularity, as far as more experience has been achieved, and modern
devices
have been developed. In some series, its accuracy has been proved in
90%
of cases, but it is still an operator-dependent exam, with a fail in at
least 10 to 15% of negative findings, even with color Doppler scans. No
lab test can confirm the diagnosis of appendicitis. Dueholm et al could
predict 100% normal appendices when WBC and C-reactive protein were
normal,
but no inverse relation could be proved. The urinalysis is important to
assess possible infection or calculi migration. Massive pyuria usually
preannounces urinary infection, but discrete findings can be due to
appendicitis.

TREATMENT

Surgical Management

Standard appendectomy through a Babcock-Davis muscle splitting
approach
is a safe, quick and efficient technique to manage appendicitis. The
stump
can be inverted, but nowadays simple ligation with electrocauterization
is the procedure of choice. In complicated cases, with perforation and
peritonitis, exhaustive cavity lavage with saline should be
accomplished.
No improvement is shown by cavity antibiotic irrigation. Drainage is
controversial
and we do not use drains for appendicitis. Abdominal wall is
approximated
with Smith-Jones sutures. Primary skin closure is performed even in
advanced
cases. Laparoscopic appendectomy has gained force in the ‘90's as
a
minimal
invasive technique, easy visualization of the structures even in
difficult
sites, e.g., retrocecal appendices, and accurate suction of purulent
material
and irrigation of the cavity with very low postoperative complication
rates
( less than 1.5%). Operative time, costs, intraoperative complications
such as a bleeding, stump leakage and visceral puncture are some
limitations
to be reduced with time and experience. A subgroup of children (obese,
female, athletic) benefit from the use of this surgical technique.

In patients with appendiceal mass or abscess, with no signs of
peritonitis
or systemic sepsis "cooling the process" with antibiotic therapy,
followed
by interval appendectomy (operating on the patient on an elective basis
free from inflammation) can be done with relative security.

Antibiotic Therapy

Prophylactic antibiotic is given one hour before surgery and
continued
for 24 hours in uncomplicated appendicitis, and must be continued for
at
least five to seven days, in cases of a complication ( perforation,
peritonitis,
abscess ). Triple combination of ampicillin (200 mg/Kg/day),
gentamicin(
5 mg/Kg/day) and clindamycin ( 40 mg/Kg/day) has shown the best results
in treating infection and preventing septic complications.

COMPLICATIONS

Major complications as intra abdominal abscesses, small bowel
obstruction
and sepsis, have declined to an overall rate of 7%, in well controlled
studies. Minor ones such as wound infection to a rate of less than 2%.

THE "NORMAL APPENDIX"

It has been common knowledge that a diagnostic error of 10 to
15%
could
be acceptable when compared with the risks of appendicitis, and some
series
stills carry this unacceptable rate, with no decrease in the
complication
rates, compared with other series. In the first 24 hours, close
attention,
and short period reexaminations, added to critical interpretation of
image
and lab studies will help decrease unnecessary surgery with no increase
in complication rates.

K.Chronic Intestinal Pseudo-Obstruction

Chronic Intestinal Pseudo-Obstruction is a rare disorder of
intestinal
motility in infants and children characterized by recurrent attacks of
abdominal pain, distension, vomiting, constipation and weight loss in
the
absence of obvious mechanical lesions. The disease can be familial or
sporadic.
Suggested etiology is degeneration of enteric nervous or smooth muscle
cells. The diagnosis is based on history, physical exam, radiographies
and motility studies. X-Ray hallmarks are: absent strictures, absent,
decreased
or disorganized intestinal motility, and dilated small/large bowel
loops.
Associated conditions identified in 10-30% of patients are bladder
dysfunction
(megacystis) and neurological problems. Histologic pattern portrayed:
myenteric
plexus hyperplasia, glial cell hyperplasia, and small ganglion cells
(hypoganglionosis).
Management is primary supportive: intestinal decompression (NG),
long-term
TPN and antibiotic prophylaxis. Motility agents are unsuccessful.
Venting
gastrostomy with home parenteral nutrition has shortened the high
hospitalization
rate associated to this disease process. A similar condition can be
seen
in early fed prematures due to immaturity of intestinal motility.

L.Bezoars

Bezoars are rare foreign body concretions formed in the stomach and
small bowel composed mainly of hair (tricho), vegetable matter (phyto)
or milk curds (lacto). Most cases are females children, 6-10 years old,
with bizarre appetite (trichophagia) and emotional disturbances.
Originally
the mass forms in the stomach and can move to the small bowel by
fragmentation,
extension or total translocation. Diagnosis can be confirmed by UGIS,
CT-Scan
or endoscopy. The child can develop an asymptomatic palpable abdominal
mass, pain, obstruction or perforation. Other children will reduce
intake
and develop weight loss. Predisposing conditions to bezoar formations
are:
gastric dymotility and decreased acidity. Management can consist of
mechanical
or pulsating jet of water fragmentation via the endoscope, operative
extraction,
shock-wave lithotripsy (ESWL) with subsequent evacuation, or
dissolution
by oral ingestion of proteolytic enzymes (papain, acetylcysteine,
cellulase).
With ESWL the shock wave pressure needed is less than half used for
urolithiasis
cases.

Intestinal Neuronal Dysplasia (IND) is a
colonic
motility disorder first described in 1971 by Meier-Ruge associated to
characteristic
histochemical changes of the bowel wall (hyperplasia of submucous &
myenteric plexus with giant ganglia formation, isolated ganglion
cells in lamina propia and muscularis mucosa, elevation of
acetylcholinesterase
in parasympathetic fiber of lamina propia and circular muscle, and
myenteric
plexus sympathetic hypoplastic innervation), also known as
hyperganglionosis
associated to elevated acetylcholinesterase parasympathetic staining.
The
condition can occur in an isolated form (either localized to colon or
disseminated
throughout the bowel), or associated to other diseases such as
Hirschsprung's
(HD), neurofibromatosis, MEN type IIB, and anorectal malformations. It
is estimated that 20-75% of HD cases have IND changes proximal to the
aganglionic
segment. Clinically two different types of isolated IND have been
described:
Type A shows symptoms of abdominal distension, enterocolitis, bloody
stools,
intestinal spasticity in imaging studies (Ba Enema) since birth, is
less
common and associated with hypoplasia of sympathetic nerves. Type B is
more frequent, symptoms are indistinguishable from that of HD, with
chronic
constipation, megacolon, and repeated episodes of bowel obstruction.
Management
depends on clinical situation; conservative for minor symptoms until
neuronal
maturation occurs around the 4th year of life, colostomy and
resectional
therapy for life threatening situations.

The most common congenital diaphragmatic hernia (CDH) is that
which
occurs through the postero-lateral defect of Bochdalek. It is caused by
failure of the pleuroperitoneal membrane to develop adequately and
close
before the intestines returning to the abdomen at the tenth week of
gestation.
The intestines then enter the pleural cavity and cause poor lung
development
leading to pulmonary hypoplasia (a reduced number of alveoli per area
of
lung tissue). This defect is postero-lateral in the diaphragm and may
vary
in size. Stomach, liver or spleen may be partly in chest as well.
Frequency
is 1:2000 live births and the natural history in prenatally diagnosed
CDH
is that 60% will die. The clinical presentation is that the newborn
becomes
rapidly cyanotic, acidotic, and has poor ventilation. Major findings
relate
to the degree of pulmonary maldevelopment. Chest films will show
intestines
in the chest. Left sided hernias are more common than right (90% on
left).
Placement of a radiopaque nasogastric tube may show the tube coiled in
the lower left chest. Higher risk factors are: early appearance of
symptoms
in life, prematurity and associated anomalies. Treatment consist of
rapid
intubation and ventilation with use of muscle relaxants, placement of a
nasogastric tube to prevent gaseous distension of the intestines and
preoperative
stabilization of arterial blood gases and acid-base status. Surgery can
be undertaken when one of the following objectives are met: (1) blood
gases
normalize with no significant changes between preductal and postductal
samples, (2) echocardiogram demonstrate reduce pulmonary pressure and
pulmonary
peripheral resistance. Operative management consist of abdominal approach, closure
of hernia by primary repair or use of mesh, and correction of
malrotation.
Postoperative management is very difficult. Due to hypoplastic lungs,
there
is frequently pulmonary hypertension leading to right-to-left shunting
and progressive hypoxemia, hypercarbia, and acidosis that worsens the
pulmonary
hypertension. The use of chest tubes may cause overstretching of the
already
hypoplastic alveoli causing: increase pulmonary hypertension, reduce
functional
residual capacity and reduce lung compliance. Postoperatively, the
infant
should be kept paralyzed and ventilated and only very slowly weaned
from
the ventilator. The severity of pulmonary hypoplasia, both
ipsilaterally
and contralaterally, is the main determinant of outcome. ECMO
(extracorporeal
membrane oxygenator) has come to reduce somewhat the mortality of this
condition. The mortality of CDH is directly related to the degree of
lung hypoplasia associated. Death is caused by persistent pulmonary
hypertension
and right ventricular failure. Prospective studies of prenatally
diagnosed
fetus prior to 25 wk. gestation has shown that 60% will die despite
optimal
postnatal care. This unsolved problem has prompted investigators to
develop
new treatment options such as preoperative stabilization, jet-frequency
ventilation, and ECMO. Another area of development is intrauterine
fetal
surgical repair. To achieve success fetal surgery should: (1)
pose
no risk to the mother (innocent bystander) or her future reproductive
capacity;
(2) tocolytic therapy in the post-op weeks should proved effective to
avoid
prenatal stillbirths; and (3) the procedure should be superior to
conventional therapy. Intrauterine repair has meet with limited success
due to herniation of the fetal liver into the chest through the defect.
Disturbance of the umbilical circulation during or after liver
reduction
causes fetal death. Positive-pressure ventilation after birth reduces
the
liver before the baby comes for surgical repair. Dr. Harrison (USFC
Fetal
Treatment Center) has devised separate fetal thoraco-abdominal
incisions
to deal with this problem ("two-step dance"), reducing or amputating
the
left lateral segment of the liver. Another less invasive approach is
enlarging
the hypoplastic lungs by reducing the normal egress of fetal lung fluid
with controlled tracheal obstruction called PLUGS (Plug Lung Until it
Grows). Delayed presentation beyond the neonatal period is rare,
estimated
to occur in 4-6% of cases. Infants and children will present with
either
respiratory or gastrointestinal symptoms such as: chronic respiratory
tract
infection, vomiting, intermittent intestinal obstruction, and feeding
difficulty.
Occasionally the child is asymptomatic. The small size of the defect
protected
by either the spleen or the liver and the presence of a hernial sac
may
delay the intestinal herniation into the chest. A rise intrabdominal
pressure
by coughing or vomiting transmitted to any defect of the diaphragm
makes
visceral herniation more likely. Diagnosis is confirmed by chest or
gastrointestinal
contrast imaging. Management consists of immediate surgery after preop
stabilization. Most defects can be closed primarily through an
abdominal
approach. Chest-tube placement in the non-hypoplastic lung is of help.
Surgical results are generally excellent. A few deaths have resulted
from
cardiovascular and respiratory compromise due to visceral herniation
causing
mediastinal and pulmonary compression.

A.2 Morgagni Hernias

First described in 1769, Morgagni Hernias (MH) are rare
congenital
diaphragmatic defects close to theanterior midline between the costal and sternal origin of the
diaphragm.
They occur retrosternally in themidline or more commonly on either side (parasternally) of the
junction
of the embryologic septumtransversum and thoracic wall (see the figure) representing less
than 2% of all diaphragmatic defects.Almost always asymptomatic, typically present in older children
or adults with minimal gastrointestinalsymptoms or as incidental finding during routine chest radiography
(mass or air-fluid levels). Infantsmay develop respiratory symptoms (tachypnea, dyspnea and cyanosis)
with distress. Cardiactamponade due to protrusion into the pericardial cavity has been
reported. The MH defect contains asac with liver, small/ large bowel as content. Associated conditions
are: heart defects, trisomy 21,omphalocele, and Cantrells' pentalogy. US and CT-Scan can
demonstrate
the defect. Management isoperative. Trans-abdominal subcostal approach is preferred with
reduction of the defect and suturing ofthe diaphragm to undersurface of sternum and posterior rectus
sheath.
Large defects with phrenicnerve displacement may need a thoracic approach. Results after
surgery
rely on associated conditions.

A.3 Esophageal Hernias

Two types of esophageal hernia recognized are the hiatal and
paraesophageal
hernia. Diagnosis ismade radiologically always and in a number of patients
endoscopically.
The hiatal hernia (HH) refers toherniation of the stomach to the chest through the esophageal
hiatus.
The lower esophageal sphincteralso moves. It can consist of a small transitory epiphrenic
loculation
(minor) up to an upside-downintrathoracic stomach (major). HH generally develops due to a
congenital,
traumatic or iatrogenic factor.Most disappear by the age of two years, but all forms of HH can
lead to peptic esophagitis fromGastroesophageal reflux. Repair of HH is determined by the pathology
of its associated reflux (causingfailure to thrive, esophagitis, stricture, respiratory symptoms)
or the presence of the stomach in thethoracic cavity. In the paraesophageal hernia (PH) variety the
stomach
migrates to the chest and thelower esophageal sphincter stays in its normal anatomic position.
PH is a frequent problem afterantireflux operations in patients without posterior crural repair.
Small PH can be observed. With anincrease in size or appearance of symptoms (reflux, gastric
obstruction,
bleeding, infarction orperforation) the PH should be repaired. The incidence of PH has
increased with the advent of thelaparoscopic fundoplication.

PROCESUS VAGINALIS REMNANTS

B.1 Inguinal Hernias

A hernia is defined as a protrusion of a portion of an
organ
or tissue through an abnormal opening. For groin (inguinal or femoral)
hernias, this protrusion is into a hernial sac. Whether or not the mere
presence of a hernial sac (or processus vaginalis) constitutes a hernia
is debated. Inguinal hernias in children are almost exclusively
indirect
type. Those rare instances of direct inguinal hernia are caused by
previous
surgery and floor disruption. An indirect inguinal hernia protrudes
through
the internal inguinal ring, within the cremaster fascia, extending down
the spermatic cord for varying distances. The direct hernia protrudes
through
the posterior wall of the inguinal canal, i.e., medial to deep inferior
epigastric vessels, destroying or stretching the transversalis fascia.
The embryology of indirect inguinal hernia is as follows: the duct
descending
to the testicle is a small offshoot of the great peritoneal sac in the
lower abdomen. During the third month of gestation, the processus
vaginalis
extends down toward the scrotum and follows the chorda gubernaculum
that
extends from the testicle or the retroperitoneum to the scrotum. During
the seventh month, the testicle descend into the scrotum, where the
processus
vaginalis forms a covering for the testicle and the serous sac in which
it resides. At about the time of birth, the portion of the processus
vaginalis
between the testicle and the abdominal cavityobliterates, leaving a peritoneal cavity separate from the tunica
vaginalis that surrounds the testicle. Approximately 1-3% of children have a hernia. For infants
born prematurely, the incidence varies from 3-5%. The typical patient
with
an inguinal hernia has an intermittent lump or bulge in the groin,
scrotum,
or labia noted at times of increased intra-abdominal pressure. A
communicating
hydrocele is always associated with a hernia. This hydrocele fluctuates
in size and is usually larger in ambulatory patients at the end of the
day. If a loop of bowel becomes entrapped (incarcerated) in a hernia,
the
patient develops pain followed by signs of intestinal obstruction. If
not
reduced, compromised blood supply (strangulation) leads to perforation
and peritonitis. Most incarcerated hernias in children can be reduced. The incidence of inguinal hernia (IH) in premature babies
(9-11%) is higher than full-term (3-5%), with a dramatic risk of
incarceration
(30%). Associated to these episodes of incarceration are chances of:
gonadal
infarction (the undescended testes complicated by a hernia are more
vulnerable
to vascular compromise and atrophy), bowel obstruction and
strangulation.
Symptomatic hernia can complicate the clinical course of babies at NICU
ill with hyaline membrane, sepsis, NEC and other conditions needing
ventilatory
support. Repair should be undertaken before hospital discharge to avoid
complications. Prematures have: poorly developed respiratory control
center,
collapsible rib cage, deficient fatigue-resistant muscular fibers in
the
diaphragm that predispose then to potential life-threatening post-op
respiratory
complications such as: need of assisted ventilation (most common),
apnea
and bradycardia, emesis, cyanosis and re-intubation (due to
laryngospasm).
Independent risk factors associated to this complications are (1)
history
of RDS/bronchopulmonary dysplasia, (2) history of patent ductus
arteriosus,
(3) low absolute weight (< 1.5 Kg), and (4) anemia (Hgb < 10 gm-
is associated to a higher incidence of post-op apnea). Postconceptual
age
(sum of intra- and extrauterine life) has been cited as the factor
having
greatest impact on post-op complications. These observation makes
imperative
that preemies (with post conceptual age of less than 45 weeks) be
carefully
monitored in-hospital for at least 24 hours after surgical repair of
their
hernias. Outpatient repair is safer for those prematures above the 60
wk.
of postconceptual age. The very low birth weight infant with
symptomatic
hernia can benefit from epidural anesthesia. At times, the indirect inguinal hernia will extend into the
scrotum and can be reduced by external, gentle pressure. Occasionally,
the hernia will present as a bulge in the soft tissue overlying the
internal
ring. It is sometimes difficult to demonstrate and the physician must
rely
on the patient's history of an intermittent bulge in the groin seen
with
crying, coughing or straining. Elective herniorrhaphy at a near convenient time is treatment
of choice. Since risk of incarceration is high in children, repair
should
be undertaken shortly after diagnosis. Simple high ligation of the sac
is all that is required. Pediatric patients are allowed to return to
full
activity immediately after hernia repair. Patients presenting with
incarceration
should have an attempt at reduction (possible in greater than 98% with
experience), and then admission for repair during that hospitalization.
Bilateral exploration is done routinely by most experienced pediatric
surgeons.
Recently the use of groin laparoscopy through the hernial sac permits
visualization
of the contralateral side. Approximately 1% of females with inguinal hernias will have
the testicular feminization syndrome. Testicular feminization syndrome
(TFS) is a genetic form of male pseudohermaphroditism (patient who is
genetically
46 XY but has deficient masculinization of external genitalia) caused
by
complete or partial resistance of end organs to the peripheral effects
of androgens. This androgenic insensitivity is caused by a mutation of
the gene for androgenic receptor inherited as an X-linked recessive
trait.
In the complete form the external genitalia appear to be female with a
rudimentary vagina, absent uterus and ovaries. The infant may present
with
inguinal hernias that at surgery may contain testes.
Axillary/pubic
hair is sparse and primary amenorrhea is present. The incomplete form
may
represent undervirilized infertile men. Evaluation should include:
karyotype,
hormonal assays, pelvic ultrasound, urethrovaginogram, gonadal biopsy
and
labial skin bx for androgen receptor assay. This patients will never
menstruate
or bear children. Malignant degeneration (germ cell tumors) of the
gonads
is increased (22-33%). Early gonadectomy is advised to: decrease the
possible
development of malignancy, avoid the latter psychological trauma to the
older child, and eliminate risk of losing the pt during follow-up.
Vaginal
reconstruction is planned when the patient wishes to be sexually
active.
These children develop into very normal appearing females that are
sterile
since no female organs are present.

B.2 Hydroceles

A hydrocele is a collection of fluid in the space surrounding the
testicle between the layers of the tunica vaginalis. Hydroceles can be
scrotal, of the cord, abdominal, or a combination of the above. A
hydrocele
of the cord is the fluid-filled remnant of the processus vaginalis
separated
from the tunica vaginalis. A communicating hydrocele is one that
communicates
with the peritoneal cavity by way of a narrow opening into a hernial
sac.
Hydroceles are common in infants. Some are associated with an inguinal
hernia. They are often bilateral, and like hernias, are more common on
the right than the left. Most hydroceles will resolved spontaneously by
1-2 years of age. After this time, elective repair can be performed at
any time. Operation is done through the groin and search made for an
associated
hernia. Aspiration of a hydrocele should never be attempted. As a
therapeutic
measure it is ineffective, and as a diagnostic tool it is a catastrophe
if a loop of bowel is entrapped. A possible exception to this is the
postoperative
recurrent hydrocele.

C. Undescended Testis

The undescended testis is a term we use to
describe
all instances in which the testis cannot be manually manipulated into
the
scrotum. The testes form from the medial portion of the urogenital
ridge
extending from the diaphragm into the pelvis. In arrested descent, they
may be found from the kidneys to the internal inguinal ring. Rapid
descent
through the internal inguinal ring commences at approximately week 28,
the left testis preceding the right. Adequate amounts of male hormones
are necessary for descent. The highest levels of male hormones in the
maternal
circulation have been demonstrated at week 28. Thus, it appears that
failure
of descent may be related to inadequate male hormone levels or to
failure
of the end-organ to respond. The undescended testes may be found
from the hilum of the kidney to the external inguinal ring. A patent
processus
vaginalis or true hernial sac will be present 90% of the time. The undescended testis found in 0.28% of males
can be palpable (80%; most at inguinal canal), ornon-palpable (20%). Testes that can be manually brought to the
scrotum
are retractile and need nofurther treatment. Parents should know the objectives, indications
and limitations of an orchiopexy: thatthe testis could not exist (testicular vanishing syndrome), even
after descend can atrophy, that it cannotbe fixed and removal is a therapeutic possibility. To improve
spermatogenesis
(producing an adequatenumber of spermatozoids) surgery should be done before the age of
two. Electron microscopy hasconfirmed an arrest in spermatogenesis (reduced number of
spermatogonias
and tubular diameter) inundescended testis after the first two years of life. Other reasons
to pex are: a higher incidence ofmalignancy, trauma and torsion, and future cosmetic and
psychological
problems in the child. Themanagement is surgical; hormonal (Human Chorionic Gonadotropin)
treatment has brought conflictingresults except bilateral cases. Surgery is limited by the length
of the testicular artery. Palpable testeshave a better prognosis than non-palpable. Laparoscopy can be of
help in non-palpable testis avoidingexploration of the absent testis.

An umbilical hernia is a small defect in the abdominal fascial
wall
in which fluid or abdominal contents protrude through the umbilical
ring.
The presence of a bulge within the umbilicus is readily palpable and
becomes
more apparent when the infant cries or during defecation. The actual
size
of the umbilical hernia is measured by physical examination of the
defect
in the rectus abdominis muscle, and not by the size of the umbilical
bulge.
The size of the fascial defect can vary from the width of a fingertip
to
several centimetres.Embryologically, the cause of an umbilical hernia
is
related to the incomplete contraction of the umbilical ring. The
herniation
of the umbilicus is a result of the growing alimentary tract that is
unable
to fit within the abdominal cavity. Umbilical hernias are more
prevalent
in females than in males and are more often seen in patients with
African
heritage. The increased frequency of umbilical hernias has also been
attributed
to premature babies, twins and infants with long umbilical cords. There
is also a frequent association with disorders of mucopolysaccharide
metabolism,
especially Hurler's Syndrome (gargoylism).Most umbilical hernias are
asymptomatic;
the decision to repair the umbilical hernia in the first years of life
is largely cosmetic and is often performed because of parental request,
not because of pain or dysfunction. In the past, some parents use to
tape
a coin over the umbilical bulge, however, manual compression does not
have
an effect on the fascial defect.Treatment of umbilical hernia is
observation.
Most umbilical hernias spontaneously close by age two, with 90% closed
by age three and 95% closed by age five. However, surgical repair is
recommended
if the hernia has not closed by the age of five.If a large defects
(> 2cm)
remains after the age of 2, spontaneously repair in unlikely and may be
closed surgically. The incidence of incarceration (trapped intestinal
loop)
is rare, even in larger defects. Females should especially have their
umbilical
hernia corrected before pregnancy because of the associated increased
intra-abdominal
pressure that could lead to complications. The procedure is simple and
incidence of complication such as infection is extremely rare. The
repair
is usually done as outpatient surgery under general anesthetic.

The three most common abdominal wall defect in newborns are
umbilical
hernia, gastroschisis andomphalocele. Omphalocele is a milder form of primary abdominoschisis
since during the embryonicfolding process the outgrowth at the umbilical ring is insufficient
(shortage in apoptotic cell death).Bowel and/or viscera remains in the umbilical cord causing a large
abdominal wall defect. Defect mayhave liver, spleen, stomach, and bowel in the sac while the
abdominal
cavity remains underdeveloped insize. The sac is composed of chorium, Wharton's jelly and
peritoneum.
The defect is centrally localizedand measures 4-10 cm in diameter. A small defect of less than 2
cm with bowel inside is referred as ahernia of the umbilical cord. There is a high incidence (30-60%)of
associated anomalies in patients withomphalocele. Epigastric localized omphalocele are associated with
sternal and intracardiac defects (i.e.,Pentalogy of Cantrell), and hypogastric omphalocele have a high
association with genito-urinarydefects (i.e., Cloacal Exstrophy). All have malrotation. Cardiac,
neurogenic, genitourinary, skeletal andchromosomal changes and syndromes are the cornerstones of mortality.
Antenatal diagnosis mayaffect management by stimulating search for associated
anomalies
and changing the site, mode ortiming of delivery. Cesarean section is warranted in large
omphaloceles
to avoid liver damage anddystocia. After initial stabilization management requires
consideration
of the size of defect, prematurityand associated anomalies. Primary closure with correction of the
malrotation should be attemptedwhenever possible. If this is not possible, then a plastic
mesh/silastic
chimney is fashioned around thedefect to cover the intestinal contents and the contents slowly
reduced over 5-14 days. Antibiotics andnutritional support are mandatory. Manage control centers around
sepsis, respiratory status, liver andbowel dysfunction from increased intraabdominal pressure.

F. Gastroschisis

Gastroschisis is a congenital evisceration of part of the
abdominal
content through an anteriorabdominal wall defect found to the right of the umbilicus. The
protruding
gut is foreshortened, matted,thickened and covered with a peel. In a few babies (4 to 23%) an
intestinal atresia (IA) furthercomplicates the pathology. IA complicating gastroschisis may be
single or multiple and may involve thesmall or large bowel. The IA might be the result of pressure
on the bowel from the edge of the defect(pinching effect) or an intrauterine vascular accident. Rarely,
the orifice may be extremely narrowleading to gangrene or complete midgut atresia. In either case the
morbidity and mortality of the child isduplicated with the presence of an IA. Management remains
controversial.
Alternatives depend on thetype of closure of the abdominal defect and the severity of the
affected bowel. With primary fascialclosure and good-looking bowel primary anastomosis is justified.
Placement of a silo calls for delayedresection performing a second look operation at a later stage
to save intestinal length. Angry lookingdilated bowel prompts for proximal diversion, but the higher the
enterostomy the greater the problemsof fluid losses, electrolyte imbalances, skin excoriation, sepsis
and malnutrition. Closure of the defectand resection with anastomosis two to four weeks later brings good
results. Success or failure isrelated to the length of remaining bowel more than the specific
method used.

V. GASTROINTESTINAL BLEEDING

A. Upper GI bleeding (Neonate)

Initially do an Apt test to determine if blood comes from
fetal
origin or maternal origin (blood swallowed by the fetus). If its of
fetal
origin then consider a coagulation profile (PT,PTT). If this
coagulation
profile is normal the possibilities are either stress gastritis or
ulcer
disease. If the coagulation profile is abnormal then consider
hematologic
disease of the newborn and manage with vitamin K. The apt test is
performed
by mixing 1 part of vomitus with 5 part H2O, centrifuge the mixture and
remove 5 ml (pink). Then add 1 ml 1% NaOH, wait 2 minutes and if it
remains
pinks is fetal blood, if it turns brown-yellow its maternal blood.

B. Lower GI bleeding (Neonate) Again start with an Apt test, if its positive its maternal
swallow blood, if its negative do a PT, PTT. If the coagulation profile
is abnormal give Vit K for hematologic disorder of newborn. If it's
normal
do a rectal exam. A fissure could be the cause, if negative then
consider
either malrotation or Necrotizing enterocolitis.

B.1 Necrotizing Enterocolitis (NEC) Although the exact pathogenesis of NEC is not known, the most
widely held theory is that of perinatal stress leading to selective
circulatory
ischemia. The stress includes prematurity, sepsis, hypoxia,
hypothermia,
and jaundice. These babies frequently have umbilical artery, vein
catheters,
have received exchange transfusions or early feeds with hyperosmolar
formulas.
The intestinal mucosal cells are highly sensitive to ischemia and
mucosal
damage leads to bacterial invasion of the intestinal wall. Gas-forming
organisms produce pneumatosis intestinalis (air in the bowel wall
readily
seen on abdominal films). Full-thickness necrosis leads to perforation,
free air and abscess formation. These usually premature infants develop
increased gastric residuals, abdominal distension, bloody stools,
acidosis
and dropping platelet count. The abdominal wall becomes reddened and
edematous.
There may be persistent masses and signs of peritonitis. Perforation
leads
to further hypoxia, acidosis and temperature instability. The acid-base
status is monitored for worsening acidosis and hypoxia. Serial platelet
counts are obtained and, with increasing sepsis, the platelet
count
drops <50,000, indicating intravascular coagulation and decreased
bone
marrow production. The white blood cell count may be high, low or
normal
and is not generally of help. Serial abdominal films are obtained to
look
for evidence of free abdominal air, a worsening picture of pneumatosis
intestinalis, or free portal air. Therapy consist initially of stopping
feeds, instituting nasogastric suctioning and beginning broad-spectrum
antibiotics (ampicillin and gentamycin). Persistent or worsening
clinical
condition and sepsis or free air on abdominal films require urgent
surgical
intervention. Attempts to preserve as much viable bowel as possible are
mandatory to prevent resultant short gut syndrome. Complicated NEC is the most common neonatal surgical emergency
of modern times, has diverse etiologies, significant mortality and
affects
mostly premature babies. The use of primary peritoneal drain (PPD) in
the
management of NEC dates from 1977. The technique is used in the very
low
birth weight premature infant (<1500 gm) with pneumoperitoneum,
metabolic
and hemodynamic instability. Consist of a right lower quadrant incision
and placement of a drainage (penrose or catheter) under local
anesthesia
with subsequent irrigation performed bedside at the NICU. Initially
used
as a temporizing measure before formal laparotomy, some patient went to
improvement without the need for further surgery (almost one-third).
They
either had an immature (fetal type) healing process or a focal
perforation
(not associated to NEC?) which healed spontaneously. Those babies not
improved
by PPD either die (20%), go on to laparotomy and half die (20%) or
develop
complications (24%). Some suggestion made are: PPD should be an adjunct
to preop stabilization, before placing drain be sure pt has NEC by
X-rays,
persistent metabolic acidosis means uncontrolled peritoneal sepsis, do
not place drain in pts with inflammatory mass or rapid development of
intraperitoneal
fluid, the longer the drainage the higher the need for laparotomy.

C. Upper GI Bleeding (Older Children)

In the initial evaluation a history should be obtained for
bleeding disorders, skin lesions, and aspirin or steroid ingestion. The
physical exam for presence of enlarged liver, spleen, masses, ascites,
or evidence of trauma or portal hypertension. Labs such as bleeding
studies
and endoscopy, contrast studies if bleeding stops. Common causes of
Upper
GI bleeding are: 1. Esophagus(a) Varices- usually presents as severe upper gastrointestinal
bleeding
in a 2-3 year old who has previously been healthy except for problems
in
the neonatal period. This is a result of extrahepatic portal
obstruction
(portal vein thrombosis most commonly), with resulting varices. The
bleeding
may occur after a period of upper respiratory symptoms and coughing.
Management
is initially conservative with sedation and bedrest; surgery ir rarely
needed. (b) Esophagitis- this is a result of persistent
gastroesophageal
reflux leading to inflammation and generally slow, chronic loss of
blood
from the weeping mucosa. Treatment consist of antacids, frequent small
feeds, occasionally medications and if not rapidly improved, then
surgical
intervention with a fundoplication of the stomach. (c) Mallory-Weiss- this is a tear of the distal esophagus
and/or gastroesophageal junction secondary to severe regurgitation.
This
was thought to be uncommon in children because it was not looked for by
endoscopy. It probably occurs more often than previously thought.
Treatment
initially is conservative and, if persistent, oversewing of the tear
through
an incision in the stomach will be successful. (d) Duplication cysts- Rare cause, they are seen on the
mesenteric
side of the intestine anywhere from the esophagus to the anus. They
bleed
when there is ectopic gastric mucosa present. Total excision is
curative. 2. Stomach (a) Gastric Erosions- managed medically in most cases. (b) Ulcer- treated medically unless there is persistent
hemorraghe,
obstruction or perforation. (c) Hematoma- usually secondary to trauma or bleeding
disorders. 3. Duodenum (a) Duodenitis- associated to acid peptic disease. (b) Hematobilia- secondary to blunt or penetrating abdominal
injury. Occasionally requires surgical intervention with local repair
or
ligation of hepatic vessels.

D. Older GI Bleeding (Older Child)

D.1 Anal Fissure

Anal fissure is the most common cause of rectal bleeding in the
first
two years of life. Outstretching ofthe anal mucocutaneous junction caused by passage of large hard
stools during defecation produces asuperficial tear of the mucosa in the posterior midline. Pain with
the next bowel movement leads toconstipation, hardened stools that continue to produce cyclic
problems.
Large fissures withsurrounding bruising should warn against child abuse. Crohn's
disease
and leukemic infiltration areother conditions to rule-out. The diagnosis is made after inspection
of the anal canal. Chronic fissuresare associated with hypertrophy of the anal papilla or a distal
skin tag. Management is directed towardthe associated constipation with stool softeners and anal
dilatations,
warm perineal baths to relax theinternal muscle spasm, and topical analgesics for pain control.
If medical therapy fails excision of thefissure with lateral sphincterotomy is performed.

D.2 Meckel's Diverticulum

Meckel's diverticulum (MD), the pathologic structure resulting
from
persistence of the embryonicvitelline duct (yolk stalk), is the most prevalent congenital
anomaly
of the GI tract. MD can be the causeof: gastrointestinal bleeding (most common complication),
obstruction,
inflammation and umbilicaldischarge in children and 50% occur within the first two years of
life. Diagnosis depends on clinicalpresentation. Rectal bleeding from MD is painless, minimal,
recurrent,
and can be identified using99mTc- pertechnetate scan; contrasts studies are unreliable.
Persistent
bleeding requires arteriographyor laparotomy if the scan is negative. Obstruction secondary to
intussusception, herniation or volvuluspresents with findings of fulminant, acute small bowel obstruction,
is diagnosed by clinical findings andcontrast enema studies. The MD is seldom diagnosed preop.
Diverticulitis
or perforation is clinicallyindistinguishable from appendicitis. Mucosal polyps or fecal
umbilical
discharge can be caused by MD.Overall, complications of Meckel's are managed by simple
diverticulectomy
or resection withanastomosis. Laparoscopy can confirm the diagnosis and allow
resection
of symptomatic cases.Removal of asymptomatic Meckel's identified incidentally should
be considered if upon palpation thereis questionable heterotopic (gastric or pancreatic) mucosa (thick
and firm consistency) present.

D.3 Juvenile Polyps

Childhood polyps are usually juvenile (80%). Histology features a
cluster of mucoid lobes surroundedby flattened mucussecreting glandular cells (mucous retention
polyp),
no malignant potential.Commonly seen in children age 310 with a peak at age 56. As a rule
only one polyp is present, butoccasionally there are two or three almost always confined to the
rectal area (within the reach of thefinger). Most common complaint is bright painless rectal bleeding.
Occasionally the polyp may prolapsethrough the rectum. Diagnosis is by barium enema, rectal exam, or
endoscopy. Removal by endoscopyis the treatment of choice. Rarely colotomy and excision are
required.

VI. PANCREATIC AND BILIARY DISORDERS

A. Pancreatitis

Uncommon disorder in childhood. Trauma (compressed injury against
spinal
column) and biliary tract disorders (choledochal cyst, cholelithiasis)
are most common cause of pancreatitis. The most common congenital
ductal
anomaly leading to pancreatitis is pancreas divisum. Most common
complaint
is mid-epigastric abdominal trauma associated with nausea and vomiting.
Diagnosis is confirmed with elevated levels of amylase and lipase.
Ultrasound
is useful to determine degree of edema and presence of pseudocyst
formation.
Treatment consists of: NPO, NG decompression, decrease acid stimulation
(H-2 blockers), aprotinin, glucagon, and anticholinergics. Pain is
relieved
with meperidine. When pancreatic serum enzymes level return to near
normal
level patient is started in low-fat diet. Antibiotic prophylaxis use is
controversial. Surgery is indicated for: abscess formation and
pseudocyst.
Pseudocysts are the result of major ductal disruptions or minor
lacerations.
Observation allows spontaneous resolution in 40-60% of cases.
Percutaneous
aspiration and catheter drainage is another alternative in management.
Follow-up studies permit determine if cavity is decreasing in size.
This
can be done outpatient teaching parents to irrigate the catheter at
home
to assure patency. Persistency beyond 6 months may need resectional
therapy.
Additional option is internal drainage (cyst-gastrostomy,
cyst-jejunostomy).
Abscess should be drained and debride. Pancreatic pseudocyst formation
is an uncommon complication of pancreatic inflammatory disease
(pancreatitis)
or trauma in children. More than half cases are caused by blunt
abdominal
trauma. Ultrasound is the most effective and non-invasive way of
diagnosing
pancreatic pseudocysts. Acute pseudocysts are managed expectantly for
4-6
wk. until spontaneous resolution occurs. 25-50% will undergo
spontaneous
resolution. Medical therapy consists of decreasing pancreatic
stimulation
and giving nutritional support. Rupture is the major complication of
conservative
management. Chronic pseudocysts (> three mo.) will benefit from
prompt
operation and internal drainage since resolution is rare. Percutaneous
catheter drainage under local anesthesia using Ultrasound or CT guided
technique is an appropriate method of first-line therapy for
non-resolving
(chronic) or enlarging pancreatic pseudocysts. The approach is
transgastric
or transcutaneous. Those cysts that fail to resolve with percutaneous
drainage
should go investigation of ductal anatomy to rule out disruption of the
main pancreatic duct. The need for further surgery (drainage or
resectional)
will depend on the status of the duct of Wirsung.

B. Biliary Atresia

Persistent conjugated hyperbilirubinemia (greater than 20% of total or
1.5 mg%) should be urgently evaluated. Initial evaluation should
include
a well-taken history and physical exam, partial and total bilirubin
determination,
type and blood group, Coomb's test, reticulocyte cell count and a
peripheral
smear. Cholestasis means a reduction in bile flow in the liver, which
depends
on the biliary excretion of the conjugated portion. Reduce flow causes
retention of biliary lipoproteins that stimulates hypercholesterolemia
causing progressive damage to the hepatic cell, fibrosis, cirrhosis and
altered liver function tests. Biliary Atresia (BA) is the most common
cause
of persistently direct (conjugated) hyperbilirubinemia in the first
three
months of life. It is characterized by progressive inflammatory
obliteration
of the extrahepatic bile ducts, an estimated incidence of one in 15,000
live births, and predominance of female patients. The disease is the
result
of an acquired inflammatory process with gradual degeneration of the
epithelium
of the extrahepatic biliary ducts causing luminal obliteration,
cholestasis,
and biliary cirrhosis. The timing of the insult after birth suggests a
viral etiology obtained transplacentally. Almost 20% of patients have
associated
anomalies such as: polysplenia, malrotation, situs inversus,
preduodenal
portal vein and absent inferior vena cava. Histopathology is
distinguished
by an inflammatory process in several dynamic stages with progressive
destruction,
scar formation, and chronic granulation tissue of bile ducts.
Physiologic
jaundice of the newborn is a common, benign, and self-limiting
condition.
In BA the patient develops insidious jaundice by the second week of
life.
The baby looks active, not acutely ill and progressively develops
acholic
stools, choluria and hepatomegaly. Non-surgical source of cholestasis
shows
a sick, low weight infant who is jaundiced since birth. The diagnostic
evaluation of the cholestatic infant should include a series of lab
tests
that can exclude perinatal infectious (TORCH titers, hepatitis
profile),
metabolic (alpha-1-antitrypsin levels), systemic and hereditary causes.
Total bilirubin in BA babies is around 6-10 mg%, with 50-80%
conjugated.
Liver function tests are nonspecific. Lipoprotein-X levels greater than
300 mg% and Gamma Glutamyl Transpeptidase (GGT) above 200 units%
suggest
the diagnosis. The presence of the yellow bilirubin pigment in the
aspirate
of duodenal content excludes the diagnosis of BA. Ultrasound study of
the
abdomen should be the first diagnostic imaging study done to
cholestatic
infants to evaluate the presence of a gallbladder, identify intra or
extrahepatic
bile ducts dilatation, and liver parenchyma echogenicity. The
postprandial
contraction of the gallbladder eliminates the possibility of BA even
when
nuclear studies are positive. Nuclear studies of bilio-enteric
excretion
(DISIDA) after pre-stimulation of the microsomal hepatic system with
phenobarbital
for 3-5 days is the diagnostic imaging test of choice. The presence of
the radio-isotope in the GI tract excludes the diagnosis of BA.
Percutaneous
liver biopsy should be the next diagnostic step. The mini-laparotomy is
the final diagnostic alternative. Those infant with radiographic
evidence
of patent extrahepatic biliary tract has no BA. Medical management of
BA
is uniformly fatal. Kasai portoenterostomy has decreased the mortality
of BA during the last 30 years. Kasai procedure consists of removing
the
obliterated extrahepatic biliary system, and anastomosing the most
proximal
part to a bowel segment. Almost three-fourth of patients will develop
portal
hypertension in spite of adequate postoperative bile flow. They will
manifest
esophageal varices, hypersplenism, and ascites. Hepatic transplantation
is reserved for those patients with failed portoenterostomy,
progressive
liver failure or late-referral to surgery.

C. Choledochal Cyst

Choledochal cyst is a rare dilatation of the common bile duct,
prevalent
in oriental patients (Japan), where >60% of patients are less than
10 years
old. The etiology is related to an abnormal pancreatic-biliary junction
(common channel theory) causing reflux of pancreatic enzymes into the
common
bile duct (trypsin and amylase). Symptoms are: abdominal pain,
obstructive
jaundice, a palpable abdominal mass, cholangitis, and pancreatitis.
Infants
develop jaundice more frequently, causing diagnostic problems with
Biliary
Atresia. Older children may show abdominal pain and mass. Jaundice is
less
severe and intermittent. Diagnosis is confirmed with Ultrasound and
corroborated
with a HIDA (or DISIDA) Scan. Choledochal cysts are classified
depending
on morphology and localization. Management is surgical and consist of
cyst
excision and roux-en-Y hepatico-jejunostomy reconstruction. Cyst
retention
penalties paid are: stricture, cholangitis, stone formation,
pancreatitis,
biliary cirrhosis, and malignancy. Long-term follow-up after surgery is
advised.

D. Cholelithiasis

With the increase use of sonography in the work-up of abdominal pain,
cholelithiasis
is diagnosed more frequent in children. Gallstones occur as consequence
of loss of solubility of bile constituents. Two types are recognize:
cholesterol
and bilirubin. Those of cholesterol are caused by supersaturation of
bile
(lithogenic) by cholesterol overproduction or bile salt deficiency.
Bilirubin
stones occur due to hemolysis (Sickle Cell, thalassemia) or bacterial
infection
of bile. Other etiologies include: Ascaris Lumbricoides infestation,
drug-induced
(ceftriaxone), ileal resection, TPN. etc. Gallbladder sludge is a
clinical
entity that when it persists can be a predisposing factor for
cholelithiasis
and cholecystitis. Laparoscopic Cholecystectomy (LC) has become the
procedure
of choice for the removal of the disease gallbladder of children. The
benefit
of this procedure in children is obvious: is safe, effective, well
tolerated,
it produces a short hospital stay, early return to activity and reduced
hospital bill. Several technical differences between the pediatric and
adult patient are: lower intrabdominal insufflation pressure, smaller
trocar
size and more lateral position of placement. Complications are related
to the initial trocar entrance as vascular and bowel injury, and those
related to the procedure itself; bile duct injury or leak. Three 5 mm
ports
and one 10 mm umbilical port is used. Pneumoperitoneum is obtained with
Veress needle insufflation or using direct insertion of blunt trocar
and
cannula. Cholangiography before any dissection of the triangle of Calot
is advised by some workers to avoid iatrogenic common bile duct
injuries
during dissection due to anomalous anatomy, it also remains the best
method
to detect common bile ducts stones. Treatment may consist of: (1)
endoscopic
sphincterotomy, (2) opened or laparoscopic choledochotomy, or (3)
transcystic
choledochoscopy and stone extraction. Children with hemolytic
disorders,
i.e. Sickle cell disease, have a high incidence of cholelithiasis and
benefit
from LC with a shorter length of postop stay and reduced morbidity.
Acalculous
cholecystitis (AC) is more commonly found in children than adults.
Two-third
of cases appear as a complication of other illness: trauma, shock,
burns,
sepsis, and operative procedures. Contributing causes mentioned are:
obstruction,
congenital tortuosity or narrowing of the cystic duct, decreased blood
flow to the gallbladder, and long-term parenteral nutrition. Males are
more commonly affected than females. Fever, nausea, vomiting, diarrhea,
dehydration and marked subhepatic tenderness are the most common
symptoms.
Other less common sx are jaundice, and abdominal mass. Labs show
leucocytosis
and abnormal liver function tests. Recently (APSA 95), two distinct
forms
of this disease have been recognized: acute, with symptom duration less
than one month and chronic, with sx greater than three months. US is
diagnostic
by demonstrating hydrops of gallbladder, increase wall thickness and
sludge.
HIDA scan with CCK stimulation may help diagnose chronic cases. In both
situations management consist of early cholecystectomy which can be
executed
using laparoscopic techniques.

E. Idiopathic Perforation of Bile Ducts

Spontaneous perforation of the common bile duct is the second cause of
surgical jaundice in infants. The perforation is generally identified
at
the junction of the cystic and common bile ducts. Most infants develop
slowly progressive bilious ascites, jaundice, and clay-colored stools.
Other patients develop an acute bile peritonitis. Diagnosis is by
ultrasound
or HIDA scan showing extravasation. Paracentesis confirms the nature of
the ascitic fluid. Management consist of intraoperative cholangiogram
(to
demonstrate area of leak), and adequate simple drainage of area.
Periportal
inflammation precludes vigorous surgical efforts that could be
disastrous.
Tube cholecystostomy placement help for post-op follow-up studies. The
leak generally seals spontaneously during the ensuing 2-3 weeks.
Prognosis
is good with no long term biliary sequelae.

Wilms tumor (WT) is the most common
intra-abdominal
malignant tumor in children affecting more than 400 children annually
in
the USA. It has a peak incidence at 3.5 years of age. WT present as a
large
abdominal or flank mass with abdominal pain, asymptomatic hematuria,
and
occasionally fever. Other presentations include malaise, weight loss,
anemia,
left varicocele (obstructed left renal vein), and hypertension. Initial
evaluation consists of: Abdominal films, Ultrasound, IVP, urinalysis,
Chest-X-rays
and Computed Tomography. The presence of a solid, intrarenal mass
causing
intrinsic distortion of the calyceal collecting system is virtually
diagnostic
of Wilms tumor. Doppler sonography of the renal vein and inferior vena
cava can exclude venous tumor involvement. Metastasis occurs most
commonly
to lungs and occasionally to liver. Operation is both for treatment and
staging to determine further therapy. Following NWTSG recommendation's primary
nephrectomy
is done for all but the largest unilateral tumors and further adjuvant
therapy is based on the surgical and pathological findings. Important
surgical
caveats consist of using a generous transverse incision, performing a
radical
nephrectomy, exploring the contralateral kidney, avoiding tumor
spillage,
and sampling suspicious lymph nodes. Nodes are biopsied to determine
extent
of disease. WT staging by NWTSG consists of: Stage I- tumor limited to kidney and completely resected. Stage II- tumor extends beyond the kidney but is completely
excised. Stage III- residual non-hematogenous tumor confined to the
abdomen. Stage IV- hematogenous metastasis. Stage V- bilateral tumors. Further treatment with chemotherapy or
radiotherapy depends on staging and histology (favorable vs.
non-favorable)
of the tumor. Non-favorable histologic characteristics are: anaplasia
(three
times enlarged nucleus, hyperchromatism, mitosis), sarcomatous or
rhabdoid
degeneration. The success in managing WT has been remarkable the result
of stratification, registry and study from the NWTSG. Disease-free
survival
is 95% for Stage I and approximately 80% for all patients. Prognosis is
poor for those children with lymph nodes, lung and liver metastasis. WT occurs either sporadic (95%), familial (1-2%)
or associated with a syndrome (2%). Such syndromes predisposing to WT
are
WAGR (Wilms, aniridia, genitourinary malformation and mental
retardation),
Beckwith-Wiedemann Syndrome (gigantism, macroglossia, pancreas cell
hyperplasia,
BWS), and Denys-Drash Syndrome (male pseudohermaphrodite,
nephropathy
and Wilms tumor, DDS). They tend to occur in younger patients. Sporadic
WT is associated in 10% of cases with isolated hemihypertrophy or
genitourinary
malformations such as hypospadia, cryptorchidism and renal fusion.
Bilateral
synchronous kidney tumors are seen in 5-10% of cases. Routine abdominal
ultrasound screening every six months up to the age of eight years is
recommended
for children at high risk for developing WT such as the above-mentioned
syndromes. It was originally thought that WT developed
after the two-hit mutational model developed for retinoblastoma: When
the
first mutation occurs before the union the sperm and egg
(constitutional
or germline mutation) the tumor is heritable and individuals are at
risk
for multiple tumors. Nonhereditary WT develops as the result of
two-postzygotic
mutations (somatic) in a single cell. The two-event hypothesis predicts
that susceptible individuals such as familial cases, those with
multifocal
disease and those with a congenital anomaly have a lower median age at
diagnosis than sporadic cases. It is now believed that several genes'
mutations
are involved in the overall WT pathogenesis. Loss of whole portions of a chromosome
is called loss of heterozygosity (LOH), a mechanism believed to
inactivate
a tumor-suppressor gene. WT has been found 50% of the time to contain
LOH
at two genetic loci: 11p13 and 11p15. WT will develop in 30% of WAGR
children.
Children with the WAGR association shows a deletion in the short arm of
chromosome 11 band 13 (11p13) but a normal 11p15 region. Up to a third
of sporadic WT have changes in the distal part of chromosome 11, a
region
that includes band p13. The region of the deletion has been named the
WT1
gene, a tumor suppressor gene that also forms a complex with another
known
tumor-suppressor, p53. WT1 gene express a regulated transcription
factor
of the zinc-finger family proteins restricted to the genitourinary
system,
spleen, dorsal mesentery of the intestines, muscles, central nervous
system
(CNS) and mesothelium. WT1 is deleted in all WAGR syndromes cases. The
important association of WT1 mutation and WAGR syndrome with intralobar
nephrogenic rests immediately suggest that WT1 expression be necessary
for the normal differentiation of nephroblasts. Only five to 10% of
sporadic
WT have thus far been shown to harbor WT1 mutations. Inactivation of
WT1
only affects organs that express this gene such as the kidney and
specific
cells of the gonads (Sertoli cells of the testis and granulosa cells of
the ovary). WT1 has been shown to cause the Denys-Drash syndrome. Most
of the mutations described in DDS patients are dominant missense
mutations. A small subset of BWS has a 11p15
duplication
or deletion. The region 11p15 has been designated WT2 gene and is
telomeric
of WT1. Beckwith- Wiedemann form of WT is also associated with IGF2, an
embryonal growth-inducing gene. This might prove that two independent
loci
may be involved in tumor formation. Candidates genes include
insulin-like
growth factor II gene (IGFII) and the tumor suppressor gene H19.
A substantial fraction of WT (without LOH at the DNA level) has been
found
to have altered imprints with resultants over expression of IGFII and
loss
of expression of the tumor suppressor H19. IGFII may be operating like
an oncogene by perpetuating nephroblast and may account for the
perilobar
rests observed in BWS patients. A gene for a familial form (FWT1) of the
tumor has also been identified in chromosome 17q. There also might be a
gene predisposing to Wilms tumor at chromosome 7p, where constitutional
translocations have been described. Mutation in p53 is associated with
tumor progression, anaplasia and poor prognosis. Most WT are probably
caused
by somatic mutations in one or more of the increasing number of WT
genes
identified. A few chromosomal regions have seen
identified
for its role in tumor progression. LOH at chromosome 16q and chromosome
1p has been implicated in progression to a more malignant or aggressive
type Wilms' tumor with adverse outcome. This occurs in approximately
20%
of patients with WT. These children have a relapse rate three times
higher
and a mortality rate twelve times higher than WT without LOH at
chromosome
1p. p53 is also associated with the so called anaplastic unfavorable
histology. Patients with WT and a diploid DNA content
(indicating low proliferation) have been found to have an excellent
prognosis.
Hyperdiploidy (high mitotic activity) is a poor prognostic feature of
Wilms
tumor, rhabdomyosarcoma and Osteosarcoma. Nephrogenic rests are precursor lesions
of WT. Two types are recognized: perilobar nephrogenic rests (PLNR)
limited
to the lobar periphery, and intralobar nephrogenic rests (ILNR) within
the lobe, renal sinus or wall of the pelvocaliceal system. The strong
association
between ILNR, aniridia and Denys-Drash syndrome where the WT1 zinc
finger
gene has been implicated suggests that this locus might be linked to
the
pathogenesis of ILNR. Also the association between BWS and some cases
of
hemihypertrophy with abnormalities of more distant loci on chromosome
11p
raises the possibility that the putative WT2 gene might be more closely
linked to PLNR. An advantage of genetic testing is that
children with sporadic aniridia, hemihypertrophy or the above discussed
syndromes known to be at high risk for developing WT can undergo
screening
of the germline DNA. This might identify if they harbor the mutation
and
need closer surveillance for tumor development.

B. Neuroblastoma & Genetics

Neuroblastoma (NB) is the most common
extracranial
solid tumor in infants. More than 500 new cases are diagnosed annually
in the United States. Most neuroblastomas (75%) arise in the
retroperitoneum
(adrenal gland and paraspinal ganglia), 20% in the posterior
mediastinum,
and 5% in the neck or pelvis. NB is a solid, highly vascular tumor with
a friable pseudocapsule. Most children present with an abdominal mass,
and one-fourth have hypertension. Other have: Horner's syndrome,
Panda's
eyes, anemia, dancing eyes or vaso-intestinal syndrome. Diagnosis is
confirmed
with the use of simple X-rays (stipple calcifications), Ultrasound, and
CT-Scan. Work-up should include: bone marrow, bone scan, myelogram (if
there is evidence of intraspinal extension), and plasma/urine tumor
markers
level: vanillylmandelic acid (VMA), homovanillic acid ( HVA) and
dopamine (DOPA). Management of NB depends on the stage of
disease at diagnosis. Localized tumors are best managed with surgical
therapy.
Partially resected or unresectable cases need chemotherapy a/o
radiotherapy
after establishing a histologic diagnosis. Independent variables
determining
prognosis are age at diagnosis and stage of disease. The Evans
classification
for NB staging comprised: Stage I - tumor confined to an organ of origin. Stage II - tumor extending beyond an organ of origin, but
not crossing the midline. Ipsilateral lymph nodes may be involved. Stage III - tumor extending beyond midline. Bilateral lymph
nodes may be involved. Stage IV - remote disease involving skeleton, bone marrow,
soft tissue or distant lymph nodes. Stage IVS - same as stage I or II with presence of disease
in liver, skin or bone marrow. Young children with stage I/II have a better outcome. A poor
outcome is characteristic of higher stages, older patients and those
with
bone cortex metastasis. Other prognostic variables are: the site of
primary
tumor development, maturity of tumor, presence of positive lymph nodes,
high levels of ferritin, neuron-specific enolase, and diploid DNA. Neuroblastoma is a malignant tumor of the
postganglionic sympathetic system that develops from the neural crest:
sympathetic ganglion cells and adrenal gland. In vitro three cell types
have been identified: 1- neuroblastic (N-type) cells that are tumorigenic. These
cells are responsible for producing cathecolamines and vasoactive
substances
which help in diagnosis and follow-up therapy. 2- the Schwannian or substrate-adherent (S-type) cells that
are non-tumorigenic, and the 3- intermediate I-cells. NB can behave seemingly benignly and
undergo
spontaneous regression, mature into a benign ganglioneuroma or most
commonly
progress to kill its host. This disparate behavior is a manifestation
that
we are dealing with related tumors with differently genetic and
biological
features associated with a spectrum of clinical behaviors. Conclusive associations with environmental
factors have not been proved in NB. Hereditary factors are important in
NB since a few cases exhibit predisposition following a dominant
pattern
of inheritance. The most characteristic cytogenetic abnormality of
neuroblastoma
is deletion of the short arm of chromosome 1 in locus 36 (1p36)
occurring
in 50 to 70% of primary diploid tumors. LOH of the short arm of
chromosome
1 is also associated with an unfavorable outcome, suggesting that a
tumor
suppression gene may be found in this region. The common region of
deletion
or LOH resides at the distal end of the short arm of chromosome 1 from
1p36.2 to 1p36.3. Loss or inactivation of a gene at this site is
critical
for progression of neuroblastoma. A few candidate genes from this site
have been mapped. LOH in chromosome 14 long arm (14q) has also been
identified
in 25-50% or neuroblastoma cells studied but no clinical behavior has
been
identified with this finding. Gain of chromosome 17 is associated with
more aggressive tumors. Another consistent chromosomal aberration
identified in 25 to 30% of NB cells is the presence of
double-minute
chromosomes, small fragments of chromatin containing multiple copies of
the oncogene N-myc produced by amplification. N-myc protooncogene is
found
on chromosome 2p and its activation results in tumor formation. The
amplified
N-myc sequence is found on extrachromosomal double minutes (DM) or on
homogeneous
staining regions (HSR) involving different chromosomes in neuroblastoma
(N-type) cell lines. N-myc amplification is strongly associated with
advance
stages of disease, rapid tumor progression and poor outcome independent
of the stage of the tumor or the age of the patient. NB tumors
associated
with N-myc amplification needs aggressive therapy. N-myc amplification
associated with deletion of 1p is correlated with a poor outcome.
Deletion
of the long arm of chromosome 1 (1q-) is also a poor prognostic sign. Though most NB cells are diploid, a good
number of them are hyperdiploid or triploid. Hyperdiploidy is a good
prognostic
feature of NB and embryonal rhabdomyosarcoma in infants, while diploid
tumors at any age and hyperdiploid in older patients carry a worse
prognosis
requiring more intensive treatment. Neuroblast cells needs nerve growth factor
(NGF) for proper differentiation. NB tumor cells do not respond to NGF
or do not express the receptor. This receptor consists of three
transmembrane
tyrosine kinase receptors (TRK-A, TRK-B, and TRK-C), known together as
the TRK receptor. TRK-A is detected in 90% of NB cells and correlates
inversely
with N-myc expression. High TRK-A levels correlate strongly with
improved
survival and plays a role in the propensity for tumors to regress or
differentiate
into a more benign nature. TRK-B is associated with more matured tumors
and TRK-C with lower stage tumors. Alteration in the NGF receptor
function
or expression promotes tumorigenesis. In conclusion, high levels of TRK
expression are associated with better prognosis, earlier stage, lower
patient
age and lack of N-myc expression. Neuroblastomas in newborns, cystic tumors,
bilateral tumors in infants, and infants less than one year of age with
neuroblastoma stage IV-S can undergo neuronal cell differentiation with
spontaneous regression. It is thought that high level of TRK-A found in
this cases might explain differentiation and regression as high level
of
this glycoprotein is associated with a favorable prognosis. Regression
might be associated with non-affected tumor cell apoptosis. Other biological markers associated with
NB are the multidrug resistance-related protein (MRP) gene, telomerase
activity and bcl-2 gene activity. MRP shows a strong correlation with
an
advanced clinical stages and poor prognosis. High telomerase activity
is
associated with poor prognosis and high N-myc amplification. The bcl-2
gene produces a protein that prevents neuronal cell death (apoptosis)
and
promotes tumor progression. Bcl-2 expression is associated with a poor
outcome. Apoptosis in NB may result in tumor progression. The RET proto-oncogene is a protein
tyrosine kinase gene (Ret protein) expressed in the cells derived from
the neural crest. The activation of RET involves a chromosomal
inversion
of the long arm of chromosome 10 that juxtaposes the tyrosine kinase
encoding
domain of RET to the amino terminal sequences of at least three
unrelated
genes. Germline mutations in the RET gene have been associated with
neuroblastoma,
pheochromocytoma, multiple endocrine neoplasia (MEN) 2, familial
medullary
thyroid carcinoma (MTC), radiation-induced thyroid papillary carcinoma,
and recently Hirschsprung's disease. RET analysis is a suitable method
to detect asymptomatic children with MEN at risk to develop MTC
allowing
us to consider thyroidectomy at a very early stage of neoplasm
development
(C-cell hyperplasia) or prophylactically. High levels of neuron specific enolase
and serum ferritin levels are associated with a poor prognosis in NB.
Nm-23
and ganglioside GD2 are still other tumor markers associated with poor
outcome, active disease and tumor progression.

C. Rhabdomyosarcoma & Genetics

Rhabdomyosarcoma (RMS), the most common
soft tissue sarcoma in infants and children, represents about 5-15% of
all malignant solid lesions. It has a peak incidence before the age of
five years, and a second surge during early adolescence. Head, neck and
pelvic malignancies are more prevalent in infancy and early childhood,
while trunk, extremity and paratesticular sites are largely a disease
of
adolescents. RMS arises from a primitive cell type and occurs in
mesenchymal
tissue at almost any body site excluding brain and bone. The
predominant
histologic type in infants and small children is embryonal
rhabdomyosarcoma,
occurring in the head and neck, genitourinary tract and
retroperitoneum.
Embryonal RMS is associated with a favorable prognosis. Botryoid RMS is
a subtype of the embryonal variety, which ordinarily extends into body
cavities such as bladder, nasopharynx, vagina, or bile duct. The
alveolar
cell type, named for a superficial similarity to the pulmonary alveoli,
is the most common form found on the muscle masses of the trunk and
extremities,
and is seen more frequently in older children and young adults.
Alveolar
RMS is associated with a poor prognosis. This unfavorable prognosis is
the result of early and wide dissemination, bones marrow involvement
and
poor response to chemotherapy. Clinical findings, diagnostic evaluation
and therapy depend upon location of the primary tumor and are beyond
the
scope of this review. Head and neck RMS are most common and occur in
the
orbit, nasopharynx, paranasal sinuses, cheek, neck, middle ear, and
larynx.
Most are treated by simple biopsy followed by combined therapy or
preoperative
chemotherapy and radiation followed by conservative resection.
Operations
for extremity lesions include wide local excision to remove as much of
gross tumor as possible. The trend in management is more chemotherapy
with
conservative surgical therapy. Survival has depended on primary site,
stage
of disease, and treatment given. Most RMS occurs sporadically. Approximately
5% are associated to syndromes such as Beckwith-Wiedemann with LOH at
the
11p15 locus, Li-Fraumeni, the neurofibromatosis-NF1 gene located on
17q11,
Basal Cell Nevus, and the Fetal Alcohol syndrome. Other risk factors in
the development of RMS include maternal use of marijuana and cocaine,
exposure
to radiation, and maternal history of stillbirth. Alveolar and embryonal RMS are the most
genetically studied sarcomas in children. The expression of a number of
human paired box-containing (PAX) genes has been correlated with
various
types of RMS. In alveolar RMS novel fusion genes encoding chimeric
fusion
proteins have been identified. The most consistent genetic mutation
identified
in more than 70% of alveolar RMS is translocation of chromosomes 2 and
13, t(2;13)q35-37;q14). The PAX3 loci in chromosome 2 fuses to the FKHR
(fork head in rhabdomyosarcoma) domain of chromosome 13 creating a
powerful
chimeric PAX3-FKHR gene that encodes an 836 amino acid fusion protein.
This information is obtained using reverse transcriptase PCR assays of
alveolar RMS or by protein immunoprecipitation with PAX3 and FKHR
antisera.
The PAX3-FKHR protein is an active transcription factor. The t(2;13)
activates
the oncogenic potential of PAX3 by dysregulating or exaggerating its
normal
function in the myogenic lineage and affecting the cellular activities
of growth, differentiation and apoptosis. Another of the reported
translocation
is t(1;13)(p36;q14) involving chromosome 1 and 13 in 10% of alveolar
RMS.
In this variant, Chromosome 1 locus encoding PAX7 fused to FKHR in
chromosome
13 resulting in another chimeric transcript PAX7-FKHR. PAX7-FKHR tumors
tend to occur in younger patients, are more often in the extremity, are
more often localized lesions and are associated with significantly
longer
event-free survival. Still, a small subset of alveolar RMS does not
contain
either fusion mutation. The PAX3-FKHR and the variant PAX7-FKHR fusions
are associated with distinct clinical phenotypes. Identification of
fusion
gene status by PCR is a useful diagnostic tool in differentiating RMS
from
other round cell tumors. Embryonal RMS contains frequent allelic
loss on chromosome 11 (11p15), a genetic feature specific for this type
of tumor. Allelic loss is manifested by the absence of one of the two
signals
in the tumor cells indicating a genetic event such as a chromosome
loss,
deletion, or mitotic recombination that eliminates one allele and the
surrounding
chromosomal region. The smallest affected region has been localized to
chromosomal region 11p15.5. The presence of a consistent region of
allelic
loss is often indicative of the presence of a tumor suppressor gene
inactivated
in the associated malignancy. The mechanism for inactivation of tumor
suppressor
genes is postulated to be a two-hit scenario in which both copies of
the
gene are sequentially inactivated: a small point mutation inactivates
one
of the two alleles, preferably the maternal side allele, and the
allelic
loss event inactivate the second allele (the paternal allele). This
leads
to over expression of the insulin-like growth factor II gene known to
play
a role in the development of embryonal tumors. Other alterations associated with embryonal
RMS are distinct patterns of chromosomal gains (chromosomes
2,7,8,12,13,17,18,
and 19) in contrast with alveolar RMS which shows genomic amplification
of chromosomal region 12q13-15 in 50% of cases. Notably, these distinct
changes predominantly involved chromosomes 2, 12, and 13 in both
subtypes.
Additionally embryonal RMS cases shows mutations of members of the RAS
gene family, a second proto-oncogene. Both tumors share alterations in
the p53 gene at the germline level contributing to increase
susceptibility
to other tumors characteristics of the Li-Fraumeni syndrome. There is
also
greater over expression of c-myc in alveolar RMS when compared with
embryonal
RMS. All this favors a multi-step origin of RMS tumors generating
phenotypic
changes of growth autonomy, abnormal differentiation and motility. The Li-Fraumeni familial cancer syndrome
is manifested by increased susceptibility of affected relatives to
develop
a diverse set of malignancies during early childhood. The major
features
of the syndrome include breast cancer, osteosarcoma, rhabdomyosarcomas
of soft tissue, glioblastoma, leukemia and adrenal cortical
carcinoma.
More than one-half of the cancers overall and nearly one-third of the
breast
cancers were diagnosed before 30 years of age. Among females, breast
cancer
is the most common. Germline mutations within a defined region of the
p53
gene have been found in families with the Li-Fraumeni syndrome.
Persistence
of the mutation in the germline suggests a defect in DNA repair in the
family member first affected. Asymptomatic carriers of p53 germline
mutation
needs closed evaluation and follow-up for early detection and treatment
in case neoplasia develops.

D. Hepatic Tumors: Hepatoblastoma

Hepatoblastoma (HB) is the most common primary malignant neoplasm
of the liver in children mostlyseen in males less than four year of age. Diagnostic work-up (US,
Scintigraphy, CT-Scan) objective ispredicting resectability and tumor extension. Diagnostic laparotomy
will decide resectability. Markersassociated to this tumor are: alpha-fetoprotein and
gamma-glutamyltransferase
II. Only reliable chancesof cure is surgical excision although half are unresectable at dx.
Unresectable tumors can be managedwith preop chemotx. Disadvantages of preop chemotx are: progressive
disease, increase morbidity,post-op complications, and toxicity. Advantages are: decrease in
tumor size, covert three-fourth casesinto resectable, although extent of surgery is not decreased. Tumor
necrosis is more extensive in pt.receiving preop chemotx. Osteoid present in tumors after chemotx
may represent an inherent ability ofthe tumor to maturate and differentiate. Diploid tumors on DNA flow
cytometry show a better prognosis.

E. Sacrococcygeal Teratoma

Sacrococcygeal teratoma (SCT) is the most common extragonadal
germ
cell tumor in neonates with anincidence of one in 30-40,000 live births. Three-fourth are females.
SCT present as a large, firm or morecommonly cystic masses that arise from the anterior surface of the
sacrum or coccyx, protruding andforming a large external mass. Histology consist of tissue from
the three germ cell layers. SCT isclassified as: mature, immature, or malignant (endodermal sinus)
and produces alpha-feto protein (AFP).Prenatal sonographic diagnostic severity criteria are: tumor size
greater than the biparietal diameter ofthe fetus, rapid tumor growth, development of placentomegaly,
polyhydramnios
and hydrops. Largetumors should benefit from cesarean section to avoid dystocia or
tumor rupture. Management consist oftotal tumor resection with coccyx (recurrence is associated with
leaving coccyx in place). Everyrecurrence of SCT should be regarded as potentially malignant.
Malignant
or immature SCT withelevated AFP after surgical resection will benefit from adjuvant
chemotherapy. Survival is 95% formature/immature tumors, but less than 80% for malignant cases.
Follow-up
should consist of (1)meticulous physical exam every 3-6 months for first three years,
(2) serial AFP determination, (3)fecal/urodynamic functional studies. Long term F/U has found a 40%
incidence of fecal and urinaryimpairment associated to either tumor compression of pelvic
structures
or surgical trauma.

The need to differentiate malignant from
benign
thyroid nodules is the most challenging predicament in
management.Present
diagnostic work-up consists of ultrasonography (US), radionuclear scans
(RNS) and fine-needle aspiration biopsy (FNAB). After reviewing our
ten-year
experience with twenty-four pediatric thyroid nodules we found nineteen
benign and five malignant lesions. Benign nodules were soft, movable,
solitary
and non-tender. Malignant nodules were found during late adolecence,
characterized
by localized tenderness, a multigandular appearance and fixation to
adjacent
tissues. US and RNS were of limited utility since malignancy was
identified
among cystic and hot nodules respectively. Suppressive thyroid hormone
therapy was useless in the few cases tried. FNAB ineighteen cases did not limit the number of thyroid resections. It
showed that the probability that amalignant nodule had suspicious or frankly malignant cytology was
60%. The specificity was 90%. Thisis the result of a higher number of patients with follicular cell
cytology in the aspirate. No attemptsshould be made to differentiate follicular adenoma from carcinoma
since capsular and vascular invasioncannot be adequately assessed by FNAB.The physical exam findings,
persistence of the nodule,progressive growth and cosmetic appearance were the main indications
for surgery. FNAB is a safeprocedure that plays a minor role in the decision to withhold
surgery.
Its greatest strength is toanticipate in case of malignancy that a more radical procedure is
probably needed. FNAB, US and RNSshould not replace clinical judgement or suspicion as the most
important
determinants in management. In spite of presenting with advanced,
multicentric
and larger tumors children have a better survival than adults.
Populations
at risk: past radiation to head and neck, nuclear waste radiation, MEN
II kindred. Clinical presentation is a solitary cervical mass or
metastatic lymph node. Diagnostic work-up should include: sonogram
(cystic
or solid), thyroid scan (cold or hot), Fine-needle aspiration
cytology(FNA),
and Chest-X-Ray (lung metastasis 20% at dx). Pathology of tumors:
papillary
(majority, psammomas bodies), follicular (vascular or capsular
invasion),
medullary (arise from C-cells, multicentric, locally invasive),
anaplastic
(rare, invasive and metastatic). Management is surgical. Complications
of surgery increase with decreasing age of patient: temporary
hypoparathyroidism,
recurrent nerve injury. Prognostic factors associated to higher
mortality
are: non-diploid DNA, psammomas bodies, over 2 cm diameter nodule, and
anaplastic histology. Follow-up for recurrence with serum thyroglobulin
level and radioisotope scans. Adjunctive therapy: thyroid suppression
and
radio-iodine for lymph nodes and pulmonary metastasis.

H. Burkitt's Lymphoma

Burkitt's lymphoma (BL) is a highly malignant tumor first
described
during the late 50's in African children (jaw), endemic in nature, and
composed of undifferentiated lympho-reticular cells with uniform
appearance.
The American BL variety is non-endemic, mostly attacks children between
8-12 years of age, predominantly (>75%) with abdominal disease such
as
unexplained mass, pain, or intussusception. The head and neck region
follows.
The tumor can appear as a localized, diffuse (multifocal,
non-resectable)
or metastatic abdominal mass (bone marrow and CNS). It's considered the
fastest growing tumor in humans with a doubling time around 12-24 hrs.
Chemotherapy is the primary treatment modality due to its effectiveness
in rapidly proliferating cells. The role of surgery is to establish the
diagnosis (using open biopsy), stage the tumor, remove localized
disease,
relieve intestinal obstruction and provide vascular access. Complete
resection
whenever possible offers the patient improved survival. Is more readily
accomplished in patients with localized bowel involvement operated on
an
emergency basis due to acute abdominal symptoms. The only predictor of
event free survival is extent of abdominal disease at diagnosis.
Debulking
(cytoreductive) procedures increases morbidity and delays initiation of
chemotherapy worsening prognosis. Extensive tumors should be managed
with
minimal procedure and immediate chemotherapy (a/o radiotherapy). Bone
marrow
and CNS involvement are ominous prognostic signs.

VIII. GYNECOLOGIC CONSIDERATIONS

A. Labial Adhesions in Infants

Minor labial adhesions is a common pediatric gynecologic problem
occasionally
confused with imperforate hymen. Most cases are in children 2-6 y/o and
involve labial adhesions secondary to diaper rash. The process causing
fusion is a natural one: two normally covered surfaces with squamous
epithelium
in contact with each other is traumatized eventually forming a fibrous
tissue union (agglutinate) between them when healing occurs. A small
opening
near the clitoris is always present through which urine escapes.This
seldom
causes symptoms except recurrent UTI if it covers the urethral meatus.
Treatment consists of applying estrogenic creams (0.1%) for two weeks.
Manual separation can be painful and adhesion recurs. Unless the
urethral
meatus is covered, there is no reason to be further aggressive in
management.
Prolonged use of estrogenic cream can cause precocious isosexual
development.

B. Ovarian Cysts

Ovarian cysts in fetus and infants are usually follicular in nature
and less than 2 cm in size. They are commonly diagnosed between the
28th
and 39th wk. of gestation by sonography. Hypotheses on etiology are:
(1)
Excessive fetal gonadotropic activity, (2) enzymatic abnormalities of
the
theca interna, and (3) abnormal stimulation by the mother HCG.
Obstetric
management consists on observation and vaginal delivery. After birth,
diagnostic
assessment and management will depend on the size and sonographic
characteristics
of the cyst. Simple anechoic cysts, and those less than 5 cm in size
can
be observed for spontaneous resolution. Cyst with fluid debris, clot,
septated
or solid (complex nature), and larger than 5 cm should undergo surgical
excision due to the higher incidence of torsion, perforation and
hemorrhage
associated to them. Percutaneous aspiration of large simple cysts with
follow-up sonography is a well-accepted therapy, preserving surgery for
recurrent or complicated cases. Surgical therapy is either cystectomy
or
oophorectomy that can result in loss of normal ovarian tissue.

C. Breast Disorders

Most breast disorders in children of either sex are benign.
Congenital
lesions are: absent or multiple breast. Transplacental hormonal
influence
in neonates may cause hyperplasia of breast tissue with predisposition
to infection (Mastitis neonatorum). Premature hyperplasia (thelarche)
in
females is the most common breast lesion in children. It occurs before
the age of eight as a disk-shaped concentric asymptomatic subareolar
mass.
Remains static until changes occur in the opposite breast 6-12 mo
later.
It can regress spontaneously or stay until puberty arrives. Biopsy may
mutilate future breast development. On the contrary, discrete breast
masses
in males cause concern and excision is warranted. Gynecomastia is
breast
enlargement cause by hormonal imbalance, usually in obese
pre-adolescent
boys. If spontaneous regression does not occur, it can be managed by
simple
mastectomy. Virginal hypertrophy is rapid breast enlargement after
puberty
due to estrogen sensitivity. If symptomatic, management is reduction
mammoplasty.

IX. PRENATAL CONGENITAL MALFORMATIONS

A. Fetal Surgery

Poor survival with neuroblastomas, diaphragmatic hernias and
necrotizing
enterocolitis requires efforts during the next few years to reduce
mortality
rates. These areas will require extensive investigation as to etiology,
unique characteristics and better management. Certain lesions such as
hydrocephalus,
hydroureteronephrosis and diaphragmatic hernias may benefit from
intrauterine
correction.

B. Fetal Intestinal Obstruction

The fetal gastrointestinal tract (foregut, midgut and hindgut)
undergoes
ventral folding between 24-28 days' gestation. By the 5-6th wk the
stomach
rotates to the right and the duodenum occludes by cell proliferation.
Recanalization
of the duodenum occurs around the 8th wk. The midgut rotation takes
place
during the 6-11th wk and the final peritoneal closure by 10th wk. The
fetal
GI tract begins ingestion and absorption of amniotic fluid by the 14th
wk. This fluid contributes to 17% effective nutrition; proximally
obstructed
gut can cause growth retardation. Fetal intestinal obstruction is
caused
by: failure of recanalization (duodenal atresia), vascular accidents
(intestinal
atresias), intrauterine volvulus, intussusception, or intraluminal
obstruction
(meconium ileus). Esophageal obstruction causes polyhydramnios, absent
visible stomach and is related to tracheo-esophageal anomalies.
Duodenal
obstruction seen as two anechoic cystic masses is associated to
aneuploidy
(trisomy 21) and polyhydramnios. Jejuno-ileal obstruction produces
dilated
anechoic (fluid-filled) serpentine masses and bowel diameter of 1-2 cm.
Large bowel obstruction is most often caused by meconium ileus,
Hirschsprung's
disease or imperforate anus. The colon assumes a large diameter and the
meconium is seen echogenic during sonography. In general the method of
delivery is not changed by the intrauterine diagnosis of intestinal
obstruction.
Timing can be affected if there is evidence of worsening intestinal
ischemia
(early delivery recommended after fetal lung maturity).

Congenital cystic adenomatoid malformation is a lung bud lesion
characterize
by dysplasia of respiratory epithelium caused by overgrowth of distal
bronchiolar
tissue. Prenatally diagnosed CCAM prognosis depends on the size of the
lung lesion and can cause: mediastinal shift, hypoplasia of normal lung
tissue, polyhydramnios, and fetal hydrops (cardiovascular shunt).
Classified
in two types based on ultrasound findings: macrocystic (lobar, > 5
mm cysts,
anechoic, favorable prognosis) and microcystic (diffuse, more solid,
echogenic,
lethal). Occurs as an isolated (sporadic) event with a low rate of
recurrence.
Survival depends on histology. Hydrops is caused by vena caval
obstruction,
heart compression and mediastinal shift. The natural history is that
some
will decrease in size, while others disappear. Should be follow with
serial
sonograms. Prenatal management for impending fetal hydrops has
consisted
of thoraco-amniotic shunts (dislodge, migrate and occlude), and
intra-uterine
fetal resection (technically feasible, reverses hydrops, allows lung
growth).
Post-natal management consist of lobectomy.

X. PEDIATRIC LAPAROSCOPY

A. Physiology of the Pneumotperitoneum

The concept behind minimally invasive
surgery
is that the size of the wound has a direct correlation with the
metabolic
and endocrine response to surgical trauma. The greater the cutting of
fascia,
muscle and nerve the higher the catecholamine and catabolic response of
the body to surgical trauma. A potential working space during
video-laparoscopic abdominal procedures in children is established with
the help of a carbon dioxide pneumoperitoneum. The most popular
technique
used in children for developing a pneumoperitoneum is the open (Hasson)
technique, usually in children less than two years of age. Closed or
percutaneous
(Veress needle) technique is mostly practice in older children and
adolescents.
Insufflation by either technique will cause an increase in
intrabdominal
pressure (IAP). Studies during congenital abdominal wall defects
closure
such as gastroschisis and omphalocele has shown that the rise in IAP
may
cause decrease venous return, decrease renal perfusion, low splanchnic
flow, and increased airway pressures. In addition, abdominal distension
causes pulmonary function abnormalities such as decreased functional
residual
capacity, basilar alveolar collapse, and intrapulmonary shunting of
deoxygenated
blood. The cardiac afterload will increase, an effect that may be
magnified
by hypovolemia. Hypotension during the establishment
of the pneumoperitoneum is a very feared complication. It could be the
result of vascular injury, arrhythmia, insufflating too much carbon
dioxide,
impending heart failure, gas embolism or the development of a
pneumothorax.
We generally insufflate a three-kilogram baby with ten millimeters of
mercury
of intra-abdominal pressure and a 70-kilogram child with a maximum of
fifteen
mm of Hg. Increase awareness of the intrinsic
effects carbon dioxide insufflation may cause in the child abdominal
cavity
is necessary. Carbon dioxide is absorbed by the diaphragmatic surfaces
and cause hypercapnia, respiratory acidosis, and pooling of blood in
vessels
with decrease cardiac output. This effect is usually controlled by the
anesthesiologist increasing minute ventilation by 10% to 20% to
maintain
normocapnia. Increase dead space or decrease functional residual
capacity
caused by the Tredelenberg position and administration of volatile
anesthetic
agents can increment this problem. High risk children where this effect
can be potentiate further are those with pre-existent
cardio-respiratory
conditions causing increase dead space, decrease pulmonary compliance
and
increase pulmonary artery pressure and resistance. It is estimated that
carbon dioxide accumulates primarily in blood and alveoli due to the
decrease
muscular components to buffer the excess absorbed gas present in
children.
After the procedure, the combination of residual carbon dioxide in the
diaphragmatic surface and water forms carbonic acid that upon
absorbtion
by the lymphatics produces referred shoulder pain. There is always a
small
risk of ventricular dysrhythmia with insufflation of carbon dioxide in
children. Some contraindications for performing
laparoscopy during the pediatric age are: history of severe
cardio-pulmonary
conditions, uncorrectable coagulopathy, prematurity, distended
abdomen
with air or ascites, and multiple abdominal scars from previous
operative
procedures.

B. Laparoscopic Cholecystectomy

Laparoscopic Cholecystectomy (LC) has
become
the procedure of choice for the removal of the disease gallbladder of
children.
The benefit of this procedure is obvious: safe, effective, and well
tolerated.
It produces a short hospital stay, early return to activity and reduced
hospital bills. Several technical differences between the pediatric and
adult patient are: lower intrabdominal insufflation pressure, smaller
trocar
size and more lateral position of placement. Complications are related
to the initial trocar entrance as vascular and bowel injury, and those
related to the procedure itself, i.e., bile duct injury or leak. Three
5 mm ports and one 10-mm umbilical port are used. Pneumoperitoneum is
obtained
with Veress needle insufflation or using direct insertion of blunt
trocar
and cannula. Cholangiography before any dissection of the triangle of
Calot
using a Kumar clamp is advised by some workers to avoid iatrogenic
common
bile duct (CBD) injuries during dissection due to anomalous anatomy,
and
the best method to detect CBD stones. Treatment of CBD stones may
consist
of:

1- endoscopic sphincterotomy followed by LC, 2- open (conventional) or laparoscopic choledochotomy,
or 3- transcystic choledochoscopy and stone extraction.

Children with hemolytic disorders,
i.e.,
Sickle cell disease, have a high incidence of cholelithiasis and
benefit
from LC with a shorter length of postop stay and reduced morbidity. San Pablo Medical Center
performed
4439 cholecystectomies from January 1990 to July 1995; 83 (1.8%) of
them
in children. LC was found superior to the open conventional procedure
reducing
the operating time, length of stay, diet resumption, and use of pain
medication.
The child is more pleased with his cosmetic results and activities are
more promptly established. We also found that CBD stones can be managed
safely with simultaneous endoscopic papillotomy and costs of LC
are
further reduced employing re-usable equipment and selective
cholangiographic
indications.

C. Laparoscopic Appendectomy

Semm, a gynecologist, is credited with
inventing
laparoscopic appendectomy in 1982. With the arrival of video-endoscopic
procedures the role of laparoscopic appendectomy in the management of
acute
appendicitis in children has been studied and compared with the
conventional
open appendectomy. General advantages of laparoscopic appendectomy
identified
are: ease and rapid localization of the appendix, ability to explore
and
lavage the entire abdominal cavity, decrease incidence of wound
infection,
less cutaneous scarring, more pleasing cosmetically, and a rapid return
of intestinal function and full activity. There is certainly some
advantage
in doing laparoscopic appendectomy in the obese child, teenage female
with
unclear etiology of symptoms, for athletes, children with chronic right
lower quadrant abdominal pain, and cases requiring interval
appendectomy.
Disadvantages are: expensive instrumentation, time-consuming and
tedious
credentialing, and the major benefit is in the postop period. Analyzing the results of several
series that compare laparoscopic vs. conventional appendectomy in the
management
of acute appendicitis we can conclude that laparoscopy produces no
difference
with open appendectomy in respect to operating room complications and
postoperative
morbidity, has a longer operating and anesthesia time, higher hospital
costs, a shorter length of stay, less postop pain, less pain medication
requirement, and shorter convalescence. One series warned that
complicated
cases of appendicitis done by laparoscopy could increase the
postoperative
infectious rate requiring readmission. Otherwise, they all favored
laparoscopic
appendectomy in the management of appendicitis. Still, unresolved issues in my mind
are: Does laparoscopic appendectomy reduce postoperative adhesions? ,
Is
it necessary to remove a normal looking appendix during a negative
diagnostic
laparoscopy performed for acute abdominal pain? , Will the increase
intrabdominal
pressure alter the diaphragmatic lymphatic translocation of bacteria
favoring
higher septic rates in complicated cases? Experimental evidence in
animal
models favors higher rates of systemic sepsis after sequential
development
of pneumoperitoneum.

D. Laparoscopy for the Undescended Testis

The undescended testis identified in 0.28%
of males can be palpable (80%) or non-palpable (20%). It is difficult
to
determine either location or absence of the non-palpable undescended
testis
by clinical examination. Imaging studies (Ultrasound, CT Scan, Magnetic
resonance, gonadal venography) are not reliable in proving its absence.
Diagnostic laparoscopy is reliable in finding the non-palpable
undescended
testis or proving its absence. Furthermore it can be combine to provide
surgical management. After reviewing several series, with non-palpable
undescended testes managed by laparoscopy the following three findings
were identified: 1- The testis is present; in either
an intra-abdominal (38%) or inguinal position (12%). Intrabdominal
testes
can be managed by first stage laparoscopic internal spermatic vessel
clipping
and cutting (Stephen-Fowler's), followed by second stage vas-based
standard
orchiopexy six to nine months later. Inguinal testes are managed by
standard
inguinal orchiopexy. 2- The testis is absent
(vanishing
testicular syndrome) as proven by blind ending vas and testicular
vessels
(36%). These children are spare an exploration. If the vas and vessels
exit the internal ring, inguinal exploration is indicated to remove any
testicular remnant as histologic evidence, although I have found useful
removing the testicular remnant by the laparoscopic approach. The
presence
of a patent processus vaginalis may suggest a distal viable testis. 3- The testis is hypoplastic,
atretic,
or atrophic (26%), in which case is removed laparoscopically. Exact anatomical localization of
the testis by laparoscopy simplifies accurate planning of operative
repair;
therefore, is an effective and safe adjunct in the management of the
cryptorchid
testis.

E. Groin Laparoscopy

The issue of contralateral exploration in
the
pediatric inguinal hernia patient has been hotly debated. Proponents of
routine contralateral exploration cite the high percentage of
contralateral
hernia a/o potential hernia found at exploration, the avoidance of the
cost of another hospitalization, psychological trauma and anxiety to
the
child and parents over a second operation, and the added risk of
anesthesia
of a second procedure. Most pediatrics surgeons habitually explore the
contralateral side. They disagree in opinions about exploration
depending
upon the primary site of inguinal hernia, age, sex and the use of
herniography
or some intra-operative technique to check the contralateral side. Recently the use of groin
laparoscopy
permits visualization of the contralateral side. The technique consists
of opening the hernial sac, introducing a 5.5-mm reusable port,
establishing
a pneumoperitoneum, and viewing with an angle laparoscope the
contralateral
internal inguinal ring to decide the existence of a hernia, which is
repaired
if present. Requires no additional incision, avoids risk of vas
deferens
injury in boys, is rapid, safe and reliable for evaluating the opposite
groin in the pediatric patient with unilateralinguinal hernia. Children
less than two years of age have a higher yield of positive
contralateral
findings.

F. Laparoscopic Splenectomy

Laparoscopic splenectomy is another safe
and
technically feasible video-endoscopic procedures in children.
Indications
are usually hematological disorders such as Idiopathic thrombocytopenic
purpura, spherocytosis, and Hodgkin's staging. Technical considerations
of the procedure are based on anatomical facts such as the variability
in the splenic blood supply, the ligaments anchoring the organ and the
size of the diseased spleen. Generally the avascular splenophrenic and
colic ligaments are cauterized, the short gastric and hilar vessels are
individually ligated with metallic clips or gastrointestinal staplers,
and the spleen is placed in a plastic bag, fracture or morzelized
until it is removed through the navel. Comparing the laparoscopic procedure
with the conventional splenectomy, the advantages are: improved
exposure,
decreased pain, improved pulmonary function, shortened hospitalization,
more rapid return to normal activities and excellent cosmetic
appearance.
Disadvantages are longer operating time, higher costs and the need to
open
5-20% of cases due to technical uncontrolled hemorrhage, such as
bleeding
from the splenic artery.

G. Laparoscopic Fundoplication

Fundoplication for the management of
symptomatic
gastroesophageal reflux (GER) is another procedure that has evolved
recently
taking advantage of minimally invasive technique. Indications for
performing
either the open or laparoscopic fundoplication is the same, namely:
life
threatening GER (asthma, cyanotic spells), chronic aspiration
syndromes,
chronic vomiting with failure to thrive, and reflux induced esophageal
stricture. Studies comparing the open versus the laparoscopic technique
in the pediatric age have found a reduced mean hospital and
postoperative
stay with laparoscopy. The lap procedure seems similar to the open
regarding
efficacy and complication rates. Costs are not excessive, they are even
lower if we take into consideration the shorter length of stay. Lower
rate
of adhesions, pulmonary and wound complications are another benefit of
the lap technique suggested. Percutaneous laparoscopic gastrostomy can
be done concomitantly for those neurologically impeded children refer
with
feeding problems and GER. Whether to do a complete (Nissen)
or partial (Toupee, Thal, or Boix-Ochoa) wrap relies on the experience
of the surgeon with the open procedure. He should continue to do
whatever
procedure he used to perform using open surgery. Long-terms results of
complications or recurrence of GER after laparoscopic fundoplication
are
still pending publication.